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...

116 Commits

Author SHA1 Message Date
Matthew Butterick 4ed851459e convert input to txexpr-attr-value (closes #17) 2 years ago
Matthew Butterick 037e280e34 support HTML comments 2 years ago
Matthew Butterick a49498717c validate a txexpr with empty attrs 2 years ago
Matthew Butterick 41d2175803
Update README.md 3 years ago
Joel Dueck 435c6e6f36
Improve specificity of errors in validate-txexpr (#15) 3 years ago
Matthew Butterick 6b15b86f99 switch from Travis to GH actions 3 years ago
Matthew Butterick c40f64292c
Update .travis.yml 4 years ago
Matthew Butterick 3572318c6d make input arg of `attr-ref` more lenient 4 years ago
Matthew Butterick 55720d8e28 switch to MIT license 4 years ago
Matthew Butterick a23367d367
Update README.md 4 years ago
Matthew Butterick 54de399d44
Update .travis.yml 4 years ago
Sage Gerard a4d36b963f omit `deleted-signal` & correct docs (#13) 5 years ago
Matthew Butterick d3f16ceebe
Update .travis.yml 5 years ago
Matthew Butterick 3aa9767ea1
Until SSL issue is repaired 5 years ago
Alex Knauth b80218b1b6 add documentation for txexpr as a match pattern (#10)
* add documentation for txexpr as a match pattern
* docs: require racket/match for examples
5 years ago
Alex Knauth f5ae897159 make txexpr a match-expander (#8 that fixes #7) 5 years ago
Matthew Butterick fb9690564a
Update .travis.yml 6 years ago
Matthew Butterick 3b6f81bccf faster 6 years ago
Matthew Butterick 7790f57b0d lazier 6 years ago
Matthew Butterick a3b407e59c stylish 6 years ago
Matthew Butterick 1b3712dc8e matchier 6 years ago
Matthew Butterick 05af5c0e21 patch `disjoin` 6 years ago
Matthew Butterick ed1ce5ba4d neater 6 years ago
Matthew Butterick b137554658 style 6 years ago
Matthew Butterick 4e3baaab17 improve test 6 years ago
Matthew Butterick b0352ee513 space 6 years ago
Matthew Butterick 96287c1f59 provide `txexpr/stx` from `txexpr/main` 6 years ago
Alex Knauth 87cd845136 Add txexpr/stx module (#5) 6 years ago
Matthew Butterick 77ea84153c
Add Rackets 6.11 & 6.12 6 years ago
Matthew Butterick 3e866506cc doc typo 7 years ago
Matthew Butterick b58e2d5ead special handling of CDATA string 7 years ago
Matthew Butterick dbe6b10b5f “leniency, always leniency” 7 years ago
Matthew Butterick c364b40bac truly minor 7 years ago
Matthew Butterick 55cacd5429 I am a terrible person 7 years ago
Matthew Butterick b9ec24bbee Test Rackets 6.7–6.10 7 years ago
Matthew Butterick 52728869c6 be more tolerant with input types 7 years ago
Matthew Butterick f2a96d8e9c nits 7 years ago
Matthew Butterick 7937a0734f whoops 7 years ago
Matthew Butterick 8547d61ba6 benign refactorings 7 years ago
Matthew Butterick 59b95ec470 use `raise-argument-error` instead of `error` 7 years ago
Matthew Butterick bde362af97 more vigorous type checking 7 years ago
Matthew Butterick 5e384b1980 add `txexpr*` (closes #4) 8 years ago
Matthew Butterick 0e2203ea7c test 6.5 and 6.6 8 years ago
Matthew Butterick d8eceff5da gentle refactoring 8 years ago
Matthew Butterick 8f9991070a adjust testing macro 8 years ago
Matthew Butterick b96d0d5e56 adjust info.rkt 8 years ago
Matthew Butterick f4db3731f5 reorg source 8 years ago
Matthew Butterick 65d7068b6d adjust license 8 years ago
Matthew Butterick f06acaf169 reduce dependencies 8 years ago
Matthew Butterick 3a6bb6b343 test 6.4 8 years ago
Matthew Butterick 5131a8564f fix `map-elements` 8 years ago
Matthew Butterick 7b3d3abee6 first versioned release 8 years ago
Matthew Butterick 50e71ec8c5 doc update 8 years ago
Matthew Butterick 0227b119e1 doc update 8 years ago
Matthew Butterick 81fff67f64 provide `empty` 8 years ago
Matthew Butterick 9f0ba36838 doc typo 8 years ago
Matthew Butterick 62a33b5abb refactoring 8 years ago
Matthew Butterick 7dd1d5f59d add `findf-txexpr` and `findf*-txexpr` 8 years ago
Matthew Butterick 5cb2d6d93e accept regular hash for `hash->attrs` 8 years ago
Matthew Butterick 65e96c8232 use hasheq rather than hash 8 years ago
Matthew Butterick 610666cbce improve further 8 years ago
Matthew Butterick fd17224249 tweak 8 years ago
Matthew Butterick c253856d69 improve error reporting in `validate-txexpr` 8 years ago
Matthew Butterick 4264ee9856 rename `make-txexpr` to `txexpr` 8 years ago
Matthew Butterick 2d16074938 update tests 8 years ago
Matthew Butterick b19609b973 Merge pull request #2 from LeifAndersen/fix-deps
Add rackunit-doc to build-deps.
8 years ago
Leif Andersen dba81bad0f Add rackunit-doc to build-deps. 8 years ago
Matthew Butterick bdf8fd9ed7 add comment 8 years ago
Matthew Butterick aa452d74c2 adjust sorting in `check-txexprs-equal?` 8 years ago
Matthew Butterick 4988ee98d5 fix `check-txexprs-equal?` bw compat issue 8 years ago
Matthew Butterick 7fe9a04b6d add `check-txexprs-equal?` 8 years ago
Matthew Butterick 5a97174df1 Update travis with 6.3 9 years ago
Matthew Butterick 858e5e4e05 add `attr-set*` and `attr-join` 9 years ago
Matthew Butterick 8c1723e87a remove typed/txexpr 9 years ago
Matthew Butterick 82bf50554d Update .travis.yml
Add 6.2.1 and allow HEAD failures
9 years ago
Matthew Butterick 23d8a3f821 update for compatibility with new macro expander 9 years ago
Matthew Butterick ba42aa00e6 Update .travis.yml 9 years ago
Matthew Butterick ffae861cba Update .travis.yml
Change 6.1.1 to 6.2
9 years ago
Matthew Butterick 26d59f809c better judgment 9 years ago
Matthew Butterick 7e32706ffd fix docs 9 years ago
Matthew Butterick 79d2daaaeb correct handling of `valid-char?` for 6.0 9 years ago
Matthew Butterick e3508b0c54 better error message 9 years ago
Matthew Butterick 0f880e6931 correct handling of style & script blocks 9 years ago
Matthew Butterick 4de4c28261 improve error message in `make-txexpr` 9 years ago
Matthew Butterick 5b0bbfa79e add update-implies 9 years ago
Matthew Butterick d89358fbf3 doc update 9 years ago
Matthew Butterick d2e4d7a555 remove unneeded typed require 9 years ago
Matthew Butterick 4ca5e027f2 consolidate untyped tests 9 years ago
Matthew Butterick 763e54f6d2 remove 'case-lambdas' 9 years ago
Matthew Butterick 676f04cfc7 Update README.md 9 years ago
Matthew Butterick 45d615c1a0 add separate test run for untyped unsafe 9 years ago
Matthew Butterick dfe91a390d add typed/txexpr 9 years ago
Matthew Butterick 58714fac14 update build dependency 9 years ago
Matthew Butterick bd19850dbd Enlarge build matrix 9 years ago
Matthew Butterick b7e0f15b89 Use my fork of travis-racket 9 years ago
Matthew Butterick a010797bb9 add travis 9 years ago
Matthew Butterick 26563ddcfc add txexpr-tags? 10 years ago
Matthew Butterick dedff2c5de replace `listof` contracts with predicates 10 years ago
Matthew Butterick 33db527d04 add `attr-ref*` 10 years ago
Matthew Butterick b701ede767 add `attrs-equal?` 10 years ago
Matthew Butterick e8539fcfcf Merge pull request #1 from samth/patch-1
Thanks.
10 years ago
Sam Tobin-Hochstadt 58dd4acc2b Add deps. 10 years ago
Matthew Butterick bb53965dc2 add replace-proc to splitf-txexpr 10 years ago
Matthew Butterick 8fd0916426 Update README.md
Use Racket server for rendered docs
10 years ago
Matthew Butterick 724a7f5ee0 Update README.md 10 years ago
Matthew Butterick 520a2b46ca small fixes 10 years ago
Matthew Butterick 3648fa77d7 Revert "repackage for compatability with v.5.3.x"
This reverts commit d9bc7e565a.
10 years ago
Matthew Butterick d9bc7e565a repackage for compatability with v.5.3.x 10 years ago
Matthew Butterick cc1d609482 documentation updates 10 years ago
Matthew Butterick 999045c9af update gitignore 10 years ago
Matthew Butterick 35ba4ae15a remove tests from precompile 10 years ago
Matthew Butterick 1146b9d267 change txexpr->html to xexpr->html 10 years ago
Matthew Butterick e3ef10b0ac add txexpr->html and validate-txexpr 10 years ago
Matthew Butterick 060f2198ef update gitignore 10 years ago
Matthew Butterick 0daab92de5 Revert "Revert "add txexpr->html""
This reverts commit 6348c1f897.
10 years ago
Matthew Butterick 6348c1f897 Revert "add txexpr->html"
This reverts commit 951f467818.
10 years ago

@ -0,0 +1,43 @@
name: CI
on: [push, pull_request]
jobs:
run:
name: "Build using Racket '${{ matrix.racket-version }}' (${{ matrix.racket-variant }})"
runs-on: ubuntu-latest
strategy:
fail-fast: false
matrix:
racket-version: ["6.6", "6.7", "6.8", "6.9", "6.10.1", "6.11", "6.12", "7.0", "7.1", "7.2", "7.3", "7.4", "7.5", "7.6", "7.7", "7.8", "7.9", "current"]
racket-variant: ["BC", "CS"]
# CS builds are only provided for versions 7.4 and up so avoid
# running the job for prior versions.
exclude:
- {racket-version: "6.6", racket-variant: "CS"}
- {racket-version: "6.7", racket-variant: "CS"}
- {racket-version: "6.8", racket-variant: "CS"}
- {racket-version: "6.9", racket-variant: "CS"}
- {racket-version: "6.10.1", racket-variant: "CS"}
- {racket-version: "6.11", racket-variant: "CS"}
- {racket-version: "6.12", racket-variant: "CS"}
- {racket-version: "7.0", racket-variant: "CS"}
- {racket-version: "7.1", racket-variant: "CS"}
- {racket-version: "7.2", racket-variant: "CS"}
- {racket-version: "7.3", racket-variant: "CS"}
steps:
- name: Checkout
uses: actions/checkout@master
- uses: Bogdanp/setup-racket@v0.11
with:
distribution: 'full'
version: ${{ matrix.racket-version }}
variant: ${{ matrix.racket-variant }}
- name: Install Txexpr and its dependencies
run: raco pkg install --auto --batch
- name: Run the tests
run: xvfb-run raco test -j 4 -p txexpr

8
.gitignore vendored

@ -1,5 +1,7 @@
# for Racket
compiled/
doc/
*~
# for Mac OS X
.DS_Store
@ -13,3 +15,9 @@ Icon
# Files that might appear on external disk
.Spotlight-V100
.Trashes
# generated documentation
scribblings/*.js
scribblings/*.css
scribblings/*.html
scribblings/pollen/*

@ -1,165 +0,0 @@
GNU LESSER GENERAL PUBLIC LICENSE
Version 3, 29 June 2007
Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
This version of the GNU Lesser General Public License incorporates
the terms and conditions of version 3 of the GNU General Public
License, supplemented by the additional permissions listed below.
0. Additional Definitions.
As used herein, "this License" refers to version 3 of the GNU Lesser
General Public License, and the "GNU GPL" refers to version 3 of the GNU
General Public License.
"The Library" refers to a covered work governed by this License,
other than an Application or a Combined Work as defined below.
An "Application" is any work that makes use of an interface provided
by the Library, but which is not otherwise based on the Library.
Defining a subclass of a class defined by the Library is deemed a mode
of using an interface provided by the Library.
A "Combined Work" is a work produced by combining or linking an
Application with the Library. The particular version of the Library
with which the Combined Work was made is also called the "Linked
Version".
The "Minimal Corresponding Source" for a Combined Work means the
Corresponding Source for the Combined Work, excluding any source code
for portions of the Combined Work that, considered in isolation, are
based on the Application, and not on the Linked Version.
The "Corresponding Application Code" for a Combined Work means the
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and utility programs needed for reproducing the Combined Work from the
Application, but excluding the System Libraries of the Combined Work.
1. Exception to Section 3 of the GNU GPL.
You may convey a covered work under sections 3 and 4 of this License
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2. Conveying Modified Versions.
If you modify a copy of the Library, and, in your modifications, a
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that uses the facility (other than as an argument passed when the
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ensure that, in the event an Application does not supply the
function or data, the facility still operates, and performs
whatever part of its purpose remains meaningful, or
b) under the GNU GPL, with none of the additional permissions of
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3. Object Code Incorporating Material from Library Header Files.
The object code form of an Application may incorporate material from
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4. Combined Works.
You may convey a Combined Work under terms of your choice that,
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c) For a Combined Work that displays copyright notices during
execution, include the copyright notice for the Library among
these notices, as well as a reference directing the user to the
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d) Do one of the following:
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suitable for, and under terms that permit, the user to
recombine or relink the Application with a modified version of
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Corresponding Source.
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e) Provide Installation Information, but only if you would otherwise
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necessary to install and execute a modified version of the
Combined Work produced by recombining or relinking the
Application with a modified version of the Linked Version. (If
you use option 4d0, the Installation Information must accompany
the Minimal Corresponding Source and Corresponding Application
Code. If you use option 4d1, you must provide the Installation
Information in the manner specified by section 6 of the GNU GPL
for conveying Corresponding Source.)
5. Combined Libraries.
You may place library facilities that are a work based on the
Library side by side in a single library together with other library
facilities that are not Applications and are not covered by this
License, and convey such a combined library under terms of your
choice, if you do both of the following:
a) Accompany the combined library with a copy of the same work based
on the Library, uncombined with any other library facilities,
conveyed under the terms of this License.
b) Give prominent notice with the combined library that part of it
is a work based on the Library, and explaining where to find the
accompanying uncombined form of the same work.
6. Revised Versions of the GNU Lesser General Public License.
The Free Software Foundation may publish revised and/or new versions
of the GNU Lesser General Public License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the
Library as you received it specifies that a certain numbered version
of the GNU Lesser General Public License "or any later version"
applies to it, you have the option of following the terms and
conditions either of that published version or of any later version
published by the Free Software Foundation. If the Library as you
received it does not specify a version number of the GNU Lesser
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If the Library as you received it specifies that a proxy can decide
whether future versions of the GNU Lesser General Public License shall
apply, that proxy's public statement of acceptance of any version is
permanent authorization for you to choose that version for the
Library.

@ -0,0 +1,9 @@
MIT License for txexpr
© 2014-2019 Matthew Butterick
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

@ -1,14 +1,27 @@
txexpr
---------------
## txexpr ![Build Status](https://github.com/mbutterick/txexpr/workflows/CI/badge.svg)
Convenience functions for working with HTML-style tagged X-expressions in Racket
Convenience functions for working with HTML-style tagged X-expressions in Racket 6.0+.
Install from the command line like so:
raco pkg install txexpr
Then require it in your Racket file:
Then require it in your Racket file, in standard mode:
(require txexpr)
In safe mode (with contracts):
(require (submod txexpr safe))
Full docs are installed with the package. You can also [read the docs here](http://pkg-build.racket-lang.org/doc/txexpr).
## License
MIT
## Project status
Full docs are installed with the package.
Complete. I will maintain the code but no major updates are planned. Certain aspects of the API and implementation could be better, because much of this code was originally written during a more naive era of personal Racketeering. Still, it gets the job done, and I personally lack enthusiasm for diving back in.

@ -1,4 +1,6 @@
#lang info
(define collection "txexpr")
(define scribblings '(("scribblings/txexpr.scrbl" ())))
(define version "0.2")
(define collection 'multi)
(define deps '("base" ["sugar" #:version "0.2"] "rackunit-lib"))
(define update-implies '("sugar"))
(define build-deps '("scribble-lib" "racket-doc" "rackunit-doc"))

@ -1,237 +0,0 @@
#lang racket/base
(require (for-syntax racket/base))
(require racket/match xml)
(module+ safe (require racket/contract))
(define-syntax (define+provide+safe stx)
(syntax-case stx ()
[(_ (proc arg ... . rest-arg) contract body ...)
#'(define+provide+safe proc contract
(λ(arg ... . rest-arg) body ...))]
[(_ name contract body ...)
#'(begin
(define name body ...)
(provide name)
(module+ safe
(provide (contract-out [name contract]))))]))
(define+provide+safe (txexpr-tag? x)
(any/c . -> . boolean?)
(symbol? x))
(define+provide+safe (txexpr-attr? x)
(any/c . -> . boolean?)
(match x
[(list (? symbol?) (? string?)) #t]
[else #f]))
(define+provide+safe (txexpr-attrs? x)
(any/c . -> . boolean?)
(match x
[(list (? txexpr-attr?) ...) #t]
[else #f]))
(define+provide+safe (txexpr-element? x)
(any/c . -> . boolean?)
(or (string? x) (txexpr? x) (symbol? x)
(valid-char? x) (cdata? x)))
(define+provide+safe (txexpr-elements? x)
(any/c . -> . boolean?)
(match x
[(list elem ...) (andmap txexpr-element? elem)]
[else #f]))
;; is it a named x-expression?
;; todo: rewrite this recurively so errors can be pinpointed (for debugging)
(define+provide+safe (txexpr? x)
(any/c . -> . boolean?)
(and (xexpr? x) ; meets basic xexpr contract
(match x
[(list (? symbol? name) rest ...) ;; is a list starting with a symbol
(or (null? rest)
(andmap txexpr-element? rest) ;; the rest is content or ...
(and (txexpr-attrs? (car rest)) (andmap txexpr-element? (cdr rest))))] ;; attr + content
[else #f])))
(define+provide+safe (make-txexpr tag [attrs null] [elements null])
;; todo?: use xexpr/c provides a nicer error message
((symbol?) (txexpr-attrs? (listof txexpr-element?))
. ->* . txexpr?)
(filter (compose1 not null?) `(,tag ,attrs ,@elements)))
(define+provide+safe (txexpr->values x)
(txexpr? . -> .
(values symbol? txexpr-attrs? (listof txexpr-element?)))
(match
; txexpr may or may not have attr
; if not, add null attr so that decomposition only handles one case
(match x
[(list _ (? txexpr-attrs?) _ ...) x]
[else `(,(car x) ,null ,@(cdr x))])
[(list tag attr content ...) (values tag attr content)]))
(define+provide+safe (txexpr->list x)
(txexpr? . -> . list?)
(define-values (tag attrs content) (txexpr->values x))
(list tag attrs content))
;; convenience functions to retrieve only one part of txexpr
(define+provide+safe (get-tag x)
(txexpr? . -> . txexpr-tag?)
(car x))
(define+provide+safe (get-attrs x)
(txexpr? . -> . txexpr-attrs?)
(define-values (tag attrs content) (txexpr->values x))
attrs)
(define+provide+safe (get-elements x)
(txexpr? . -> . (listof txexpr-element?))
(define-values (tag attrs elements) (txexpr->values x))
elements)
;; helpers. we are getting a string or symbol
(define+provide+safe (->txexpr-attr-key x)
(can-be-txexpr-attr-key? . -> . txexpr-attr-key?)
(if (string? x) (string->symbol x) x))
(define+provide+safe (->txexpr-attr-value x)
(can-be-txexpr-attr-value? . -> . txexpr-attr-value?)
(->string x))
(define+provide+safe (txexpr-attr-key? x)
(any/c . -> . boolean?)
(symbol? x))
(define+provide+safe (can-be-txexpr-attr-key? x)
(any/c . -> . boolean?)
(or (symbol? x) (string? x)))
(define+provide+safe (txexpr-attr-value? x)
(any/c . -> . boolean?)
(string? x))
(define+provide+safe (can-be-txexpr-attr-value? x)
(any/c . -> . boolean?)
(can-be-txexpr-attr-key? x))
(define (->string x)
(if (symbol? x) (symbol->string x) x))
(define+provide+safe (can-be-txexpr-attrs? x)
(any/c . -> . boolean?)
(ormap (λ(test) (test x)) (list txexpr-attr? txexpr-attrs? can-be-txexpr-attr-key? can-be-txexpr-attr-value?)))
(define (flatten orig-sexp)
(let loop ([sexp orig-sexp] [acc null])
(cond [(null? sexp) acc]
[(pair? sexp) (loop (car sexp) (loop (cdr sexp) acc))]
[else (cons sexp acc)])))
(define+provide+safe (attrs->hash . items)
(() #:rest (listof can-be-txexpr-attrs?) . ->* . hash?)
;; can be liberal with input because they're all just nested key/value pairs
;; but still need this function to make sure that 'foo and "foo" are treated as the same hash key
(define (make-key-value-list items)
(if (null? items)
null
(let ([key (->txexpr-attr-key (car items))]
[value (->txexpr-attr-value (cadr items))]
[rest (cddr items)])
(cons (cons key value) (make-key-value-list rest)))))
(make-immutable-hash (make-key-value-list (flatten items))))
(define+provide+safe (hash->attrs hash)
(hash? . -> . txexpr-attrs?)
(hash-map hash list))
(define+provide+safe (attrs-have-key? x key)
((or/c txexpr-attrs? txexpr?) can-be-txexpr-attr-key? . -> . boolean?)
(define attrs (if (txexpr-attrs? x) x (get-attrs x)))
(hash-has-key? (attrs->hash attrs) (->txexpr-attr-key key)))
(define+provide+safe (attr-set tx key value)
(txexpr? can-be-txexpr-attr-key? can-be-txexpr-attr-value? . -> . txexpr?)
(define new-attrs
(hash->attrs (hash-set (attrs->hash (get-attrs tx)) (->txexpr-attr-key key) (->txexpr-attr-value value))))
(make-txexpr (get-tag tx) new-attrs (get-elements tx)))
(define+provide+safe (attr-ref tx key)
(txexpr? can-be-txexpr-attr-key? . -> . txexpr-attr-value?)
(with-handlers ([exn:fail? (λ(e) (error (format "attr-ref: no value found for key ~v" key)))])
(hash-ref (attrs->hash (get-attrs tx)) key)))
;; convert list of alternating keys & values to attr
(define+provide+safe (merge-attrs . items)
(() #:rest (listof can-be-txexpr-attrs?) . ->* . txexpr-attrs?)
(define attrs-hash (apply attrs->hash items))
;; sort needed for predictable results for unit tests
(define sorted-hash-keys (sort (hash-keys attrs-hash) (λ(a b) (string<? (->string a) (->string b)))))
`(,@(map (λ(key) (list key (hash-ref attrs-hash key))) sorted-hash-keys)))
(define+provide+safe (remove-attrs x)
(txexpr? . -> . txexpr?)
(cond
[(txexpr? x) (let-values ([(tag attr elements) (txexpr->values x)])
(make-txexpr tag null (remove-attrs elements)))]
[(txexpr-elements? x) (map remove-attrs x)]
[else x]))
;; todo: exclude-proc will keep things out, but is there a way to keep things in?
(define+provide+safe (map-elements/exclude proc x exclude-test)
(procedure? txexpr? procedure? . -> . txexpr?)
(cond
[(txexpr? x)
(if (exclude-test x)
x
(let-values ([(tag attr elements) (txexpr->values x)])
(make-txexpr tag attr
(map (λ(x)(map-elements/exclude proc x exclude-test)) elements))))]
;; externally the function only accepts txexpr,
;; but internally we don't care
[else (proc x)]))
(define+provide+safe (map-elements proc x)
(procedure? txexpr? . -> . txexpr?)
(map-elements/exclude proc x (λ(x) #f)))
;; function to split tag out of txexpr
(define+provide+safe (splitf-txexpr tx proc)
(txexpr? procedure? . -> . (values txexpr? (listof txexpr-element?)))
(define matches null)
(define (do-extraction x)
(cond
[(proc x) (begin ; store matched item but return null value
(set! matches (cons x matches))
null)]
[(txexpr? x) (let-values([(tag attr body) (txexpr->values x)])
(make-txexpr tag attr (do-extraction body)))]
[(txexpr-elements? x) (filter (compose1 not null?) (map do-extraction x))]
[else x]))
(define tx-extracted (do-extraction tx)) ;; do this first to fill matches
(values tx-extracted (reverse matches)))
(define+provide+safe (txexpr->html x)
(txexpr? . -> . string?)
(define (->cdata x)
(if (cdata? x) x (cdata #f #f x)))
(xexpr->string (let loop ([x x])
(cond
[(txexpr? x) (if (member (get-tag x) '(script style))
(make-txexpr (get-tag x) (get-attrs x) (map ->cdata (get-elements x)))
(make-txexpr (get-tag x) (get-attrs x) (map loop (get-elements x))))]
[else x]))))

@ -1,418 +0,0 @@
#lang scribble/manual
@(require scribble/eval (for-label racket "../main.rkt" xml))
@(define my-eval (make-base-eval))
@(my-eval `(require txexpr xml))
@title{txexpr: Tagged X-expressions}
@author[(author+email "Matthew Butterick" "mb@mbtype.com")]
@defmodule[#:multi (txexpr (submod txexpr safe))]
A set of small but handy functions for improving the readability and reliability of programs that operate on tagged X-expressions (for short, @italic{txexpr}s).
@section{Installation}
At the command line:
@verbatim{raco pkg install txexpr}
After that, you can update the package from the command line:
@verbatim{raco pkg update txexpr}
@section{Importing the module}
The module operates in two modes: fast and safe. Fast mode is the default, which you get by importing the module in the usual way: @code{(require txexpr)}.
Safe mode enables the function contracts documented below. Use safe mode by importing the module as @code{(require (submod txexpr safe))}.
@section{Whats a txexpr?}
It's an X-expression with the following grammar:
@racketgrammar*[
#:literals (cons list symbol? string? xexpr?)
[txexpr (list tag (list attr ...) element ...)
(cons tag (list element ...))]
[tag symbol?]
[attr (list key value)]
[key symbol?]
[value string?]
[element xexpr?]
]
A txexpr is a list with a symbol in the first position — the @italic{tag} — followed by a series of @italic{elements}, which are other X-expressions. Optionally, a txexpr can have a list of @italic{attributes} in the second position.
@examples[#:eval my-eval
(txexpr? '(span "Brennan" "Dale"))
(txexpr? '(span "Brennan" (em "Richard") "Dale"))
(txexpr? '(span [[class "hidden"][id "names"]] "Brennan" "Dale"))
(txexpr? '(span lt gt amp))
(txexpr? '("We really" "should have" "a tag"))
(txexpr? '(span [[class not-quoted]] "Brennan"))
(txexpr? '(span [class "hidden"] "Brennan" "Dale"))
]
The last one is a common mistake. Because the keyvalue pair is not enclosed in a @racket[list], it's interpreted as a nested txexpr within the first txexpr, as you may not find out until you try to read its attributes:
@margin-note{There's no way of eliminating this ambiguity, short of always requiring an attribute list — empty if necessary — in your txexpr. See also @racket[xexpr-drop-empty-attributes].}
@examples[#:eval my-eval
(get-attrs '(span [class "hidden"] "Brennan" "Dale"))
(get-elements '(span [class "hidden"] "Brennan" "Dale"))
]
Tagged X-expressions are most commonly found in HTML & XML documents. Though the notation is different in Racket, the data structure is identical:
@examples[#:eval my-eval
(xexpr->string '(span [[id "names"]] "Brennan" (em "Richard") "Dale"))
(string->xexpr "<span id=\"names\">Brennan<em>Richard</em>Dale</span>")
]
After converting to and from HTML, we get back the original X-expression. Well, almost. The brackets turned into parentheses — no big deal, since they mean the same thing in Racket. Also, per its usual practice, @racket[string->xexpr] added an empty attribute list after @racket[em]. This is also benign.
@section{Why not just use @exec{match}, @exec{quasiquote}, and so on?}
If you prefer those, please do. But I've found two benefits to using module functions:
@bold{Readability.} In code that already has a lot of matching and quasiquoting going on, these functions make it easy to see where & how txexprs are being used.
@bold{Reliability.} Because txexprs come in two close but not quite equal forms, careful coders will always have to take both cases into account.
The programming is trivial, but the annoyance is real.
@section{Interface}
@deftogether[(
@defproc[
(txexpr?
[v any/c])
boolean?]
@defproc[
(txexpr-tag?
[v any/c])
boolean?]
@defproc[
(txexpr-attr?
[v any/c])
boolean?]
@defproc[
(txexpr-attr-key?
[v any/c])
boolean?]
@defproc[
(txexpr-attr-value?
[v any/c])
boolean?]
@defproc[
(txexpr-element?
[v any/c])
boolean?]
)]
Predicates for @racket[_txexpr]s that implement this grammar:
@racketgrammar*[
#:literals (cons list symbol? string? xexpr?)
[txexpr (list tag (list attr ...) element ...)
(cons tag (list element ...))]
[tag symbol?]
[attr (list key value)]
[key symbol?]
[value string?]
[element xexpr?]
]
@deftogether[(
@defproc[
(txexpr-attrs?
[v any/c])
boolean?]
@defproc[
(txexpr-elements?
[v any/c])
boolean?]
)]
Shorthand for @code{(listof txexpr-attr?)} and @code{(listof txexpr-element?)}.
@deftogether[(
@defproc[
(can-be-txexpr-attr-key?
[v any/c])
boolean?]
@defproc[
(can-be-txexpr-attr-value?
[v any/c])
boolean?]
)]
Predicates for input arguments that are trivially converted to an attribute @racket[_key] or @racket[_value]…
@deftogether[(
@defproc[
(->txexpr-attr-key
[v can-be-txexpr-attr-key?])
txexpr-attr-key?]
@defproc[
(->txexpr-attr-value
[v can-be-txexpr-attr-value?])
txexpr-attr-value?]
)]
 with these conversion functions.
@defproc[
(txexpr->values
[tx txexpr?])
(values txexpr-tag? txexpr-attrs? txexpr-elements?)]
Dissolves a @racket[_txexpr] into its components and returns all three.
@examples[#:eval my-eval
(txexpr->values '(div))
(txexpr->values '(div "Hello" (p "World")))
(txexpr->values '(div [[id "top"]] "Hello" (p "World")))
]
@defproc[
(txexpr->list
[tx txexpr?])
(list txexpr-tag?
txexpr-attrs?
txexpr-elements?)]
Like @racket[txexpr->values], but returns the three components in a list.
@examples[#:eval my-eval
(txexpr->list '(div))
(txexpr->list '(div "Hello" (p "World")))
(txexpr->list '(div [[id "top"]] "Hello" (p "World")))
]
@deftogether[(
@defproc[
(get-tag
[tx txexpr?])
txexpr-tag?]
@defproc[
(get-attrs
[tx txexpr?])
txexpr-attr?]
@defproc[
(get-elements
[tx txexpr?])
(listof txexpr-element?)]
)]
Accessor functions for the individual pieces of a @racket[_txexpr].
@examples[#:eval my-eval
(get-tag '(div [[id "top"]] "Hello" (p "World")))
(get-attrs '(div [[id "top"]] "Hello" (p "World")))
(get-elements '(div [[id "top"]] "Hello" (p "World")))
]
@defproc[
(make-txexpr
[tag txexpr-tag?]
[attrs txexpr-attrs? @empty]
[elements txexpr-elements? @empty])
txexpr?]
Assemble a @racket[_txexpr] from its parts. If you don't have attributes, but you do have elements, you'll need to pass @racket[empty] as the second argument. Note that unlike @racket[xml->xexpr], if the attribute list is empty, it's not included in the resulting expression.
@examples[#:eval my-eval
(make-txexpr 'div)
(make-txexpr 'div '() '("Hello" (p "World")))
(make-txexpr 'div '[[id "top"]])
(make-txexpr 'div '[[id "top"]] '("Hello" (p "World")))
(define tx '(div [[id "top"]] "Hello" (p "World")))
(make-txexpr (get-tag tx)
(get-attrs tx) (get-elements tx))
]
@defproc[
(can-be-txexpr-attrs?
[v any/c])
boolean?]
Predicate for functions that handle @racket[_txexpr-attrs]. Covers values that are easily converted into pairs of @racket[_attr-key] and @racket[_attr-value]. Namely: single @racket[_xexpr-attr]s, lists of @racket[_xexpr-attr]s (i.e., what you get from @racket[get-attrs]), or interleaved symbols and strings (each pair will be concatenated into a single @racket[_xexpr-attr]).
@deftogether[(
@defproc[
(attrs->hash [x can-be-txexpr-attrs?] ...)
hash?]
@defproc[
(hash->attrs
[h hash?])
txexpr-attrs?]
)]
Convert @racket[_attrs] to an immutable hash, and back again.
@examples[#:eval my-eval
(define tx '(div [[id "top"][class "red"]] "Hello" (p "World")))
(attrs->hash (get-attrs tx))
(hash->attrs '#hash((class . "red") (id . "top")))
]
@defproc[
(attrs-have-key?
[attrs (or/c txexpr-attrs? txexpr?)]
[key can-be-txexpr-attr-key?])
boolean?]
Returns @racket[#t] if the @racket[_attrs] contain a value for the given @racket[_key], @racket[#f] otherwise.
@examples[#:eval my-eval
(define tx '(div [[id "top"][class "red"]] "Hello" (p "World")))
(attrs-have-key? tx 'id)
(attrs-have-key? tx 'grackle)
]
@defproc[
(attr-ref
[tx txexpr?]
[key can-be-txexpr-attr-key?])
txexpr-attr-value?]
Given a @racket[_key], look up the corresponding @racket[_value] in the attributes of a @racket[_txexpr]. Asking for a nonexistent key produces an error.
@examples[#:eval my-eval
(attr-ref tx 'class)
(attr-ref tx 'id)
(attr-ref tx 'nonexistent-key)
]
@defproc[
(attr-set
[tx txexpr?]
[key can-be-txexpr-attr-key?]
[value txexpr-attr-value?])
txexpr?]
Given a @racket[_txexpr], set the value of attribute @racket[_key] to @racket[_value]. The function returns the updated @racket[_txexpr].
@examples[#:eval my-eval
(define tx '(div [[class "red"][id "top"]] "Hello" (p "World")))
(attr-set tx 'id "bottom")
(attr-set tx 'class "blue")
(attr-set (attr-set tx 'id "bottom") 'class "blue")
]
@defproc[
(merge-attrs
[attrs (listof can-be-txexpr-attrs?)] ...)
txexpr-attrs?]
Combine a series of attributes into a single @racket[_txexpr-attrs] item. This function addresses three annoyances that surface in working with txexpr attributes.
@itemlist[#:style 'ordered
@item{You can pass the attributes in multiple forms. See @racket[can-be-txexpr-attrs?] for further details.}
@item{Attributes with the same name are merged, with the later value taking precedence (i.e., @racket[hash] behavior). }
@item{Attributes are sorted in alphabetical order.}]
@examples[#:eval my-eval
(define tx '(div [[id "top"][class "red"]] "Hello" (p "World")))
(define tx-attrs (get-attrs tx))
tx-attrs
(merge-attrs tx-attrs 'editable "true")
(merge-attrs tx-attrs 'id "override-value")
(define my-attr '(id "another-override"))
(merge-attrs tx-attrs my-attr)
(merge-attrs my-attr tx-attrs)
]
@defproc[
(remove-attrs
[tx txexpr?])
txexpr?]
Recursively remove all attributes.
@examples[#:eval my-eval
(define tx '(div [[id "top"]] "Hello" (p [[id "lower"]] "World")))
(remove-attrs tx)
]
@defproc[
(map-elements
[proc procedure?]
[tx txexpr?])
txexpr?]
Recursively apply @racket[_proc] to all elements, leaving tags and attributes alone. Using plain @racket[map] will only process elements at the top level of the current @racket[_txexpr]. Usually that's not what you want.
@examples[#:eval my-eval
(define tx '(div "Hello!" (p "Welcome to" (strong "Mars"))))
(define upcaser (λ(x) (if (string? x) (string-upcase x) x)))
(map upcaser tx)
(map-elements upcaser tx)
]
In practice, most @racket[_xexpr-element]s are strings. But woe befalls those who pass string procedures to @racket[map-elements], because an @racket[_xexpr-element] can be any kind of @racket[xexpr?], and an @racket[xexpr?] is not necessarily a string.
@examples[#:eval my-eval
(define tx '(p "Welcome to" (strong "Mars" amp "Sons")))
(map-elements string-upcase tx)
(define upcaser (λ(x) (if (string? x) (string-upcase x) x)))
(map-elements upcaser tx)
]
@defproc[
(map-elements/exclude
[proc procedure?]
[tx txexpr?]
[exclude-test (txexpr? . -> . boolean?)])
txexpr?]
Like @racket[map-elements], but skips any @racket[_txexprs] that evaluate to @racket[#t] under @racket[_exclude-test]. The @racket[_exclude-test] gets a whole txexpr as input, so it can test any of its parts.
@examples[#:eval my-eval
(define tx '(div "Hello!" (p "Welcome to" (strong "Mars"))))
(define upcaser (λ(x) (if (string? x) (string-upcase x) x)))
(map-elements upcaser tx)
(map-elements/exclude upcaser tx (λ(x) (equal? (get-tag x) 'strong)))
]
Be careful with the wider consequences of exclusion tests. When @racket[_exclude-test] is true, the @racket[_txexpr] is excluded, but so is everything underneath that @racket[_txexpr]. In other words, there is no way to re-include (un-exclude?) elements nested under an excluded element.
@examples[#:eval my-eval
(define tx '(div "Hello!" (p "Welcome to" (strong "Mars"))))
(define upcaser (λ(x) (if (string? x) (string-upcase x) x)))
(map-elements upcaser tx)
(map-elements/exclude upcaser tx (λ(x) (equal? (get-tag x) 'p)))
(map-elements/exclude upcaser tx (λ(x) (equal? (get-tag x) 'div)))
]
@defproc[
(splitf-txexpr
[tx txexpr?]
[pred procedure?])
(values txexpr? (listof txexpr-element?))]
Recursively descend through @racket[_txexpr] and extract all elements that match @racket[_pred]. Returns two values: a @racket[_txexpr] with the matching elements removed, and the list of matching elements. Sort of esoteric, but I've needed it more than once, so here it is.
@examples[#:eval my-eval
(define tx '(div "Wonderful day" (meta "weather" "good") "for a walk"))
(define remove? (λ(x) (and (txexpr? x) (equal? 'meta (get-tag x)))))
(splitf-txexpr tx remove?)
]
@section{License & source code}
This module is licensed under the LGPL.
Source repository at @link["http://github.com/mbutterick/txexpr"]{http://github.com/mbutterick/txexpr}. Suggestions & corrections welcome.

@ -1,120 +0,0 @@
#lang racket/base
(require (for-syntax racket/base))
(require (submod "main.rkt" safe) rackunit)
(define-syntax (values->list stx)
(syntax-case stx ()
[(_ values-expr) #'(call-with-values (λ () values-expr) list)]))
(check-true (txexpr-tag?'foo))
(check-false (txexpr-tag? "foo"))
(check-false (txexpr-tag? 3))
(check-true (txexpr-attr? '(key "value")))
(check-false (txexpr-attr? '(key "value" "another")))
(check-false (txexpr-attr? '(key 0 "value")))
(check-true (txexpr-attrs? '()))
(check-true (txexpr-attrs? '((key "value"))))
(check-true (txexpr-attrs? '((key "value") (foo "bar"))))
(check-false (txexpr-attrs? '((key "value") "foo" "bar"))) ; content, not attr
(check-false (txexpr-attrs? '(key "value"))) ; not a nested list
(check-false (txexpr-attrs? '(("key" "value")))) ; two strings
(check-false (txexpr-attrs? '((key value)))) ; two symbols
(check-true (txexpr-element? "string"))
(check-true (txexpr-element? 'amp))
(check-true (txexpr-element? '(p "string")))
(check-true (txexpr-element? 65)) ;; a valid-char
(check-false (txexpr-element? 0)) ;; not a valid-char
(check-true (txexpr-elements? '("p" "foo" "123")))
(check-true (txexpr-elements? '("p" "foo" 123))) ; includes number
(check-true (txexpr-elements? '(p "foo" "123"))) ; includes symbol
(check-false (txexpr-elements? "foo")) ; not a list
(check-false (txexpr-elements? '(((key "value")) "foo" "bar"))) ; includes attr
(check-false (txexpr-elements? '("foo" "bar" ((key "value"))))) ; malformed
(check-true (txexpr? '(p)))
(check-true (txexpr? '(p "foo" "bar")))
(check-true (txexpr? '(p ((key "value")) "foo" "bar")))
(check-true (txexpr? '(p 123))) ; content is a number
(check-false (txexpr? "foo")) ; not a list with symbol
(check-false (txexpr? '(p "foo" "bar" ((key "value"))))) ; malformed
(check-false (txexpr? '("p" "foo" "bar"))) ; no name
(check-equal? (make-txexpr 'p) '(p))
(check-equal? (make-txexpr 'p '((key "value"))) '(p ((key "value"))))
(check-equal? (make-txexpr 'p null '("foo" "bar")) '(p "foo" "bar"))
(check-equal? (make-txexpr 'p '((key "value")) (list "foo" "bar"))
'(p ((key "value")) "foo" "bar"))
(check-equal? (values->list (txexpr->values '(p)))
(values->list (values 'p null null)))
(check-equal? (values->list (txexpr->values '(p "foo")))
(values->list (values 'p null '("foo"))))
(check-equal? (values->list (txexpr->values '(p ((key "value")))))
(values->list (values 'p '((key "value")) null)))
(check-equal? (values->list (txexpr->values '(p ((key "value")) "foo")))
(values->list (values 'p '((key "value")) '("foo"))))
(check-equal? (values->list (txexpr->values '(p)))
(txexpr->list '(p)))
(check-equal? (values->list (txexpr->values '(p "foo")))
(txexpr->list '(p "foo")))
(check-equal? (values->list (txexpr->values '(p ((key "value")))))
(txexpr->list '(p ((key "value")))))
(check-equal? (values->list (txexpr->values '(p ((key "value")) "foo")))
(txexpr->list '(p ((key "value")) "foo")))
(check-equal? (get-tag '(p ((key "value"))"foo" "bar" (em "square"))) 'p)
(check-equal? (get-attrs '(p ((key "value"))"foo" "bar" (em "square"))) '((key "value")))
(check-equal? (get-elements '(p ((key "value"))"foo" "bar" (em "square")))
'("foo" "bar" (em "square")))
(check-equal? (->txexpr-attr-key "foo") 'foo)
(check-equal? (->txexpr-attr-key 'foo) 'foo)
(check-equal? (->txexpr-attr-value "foo") "foo")
(check-equal? (->txexpr-attr-value 'foo) "foo")
(check-equal? (attrs->hash '((foo "bar"))) '#hash((foo . "bar")))
(check-equal? (attrs->hash '((foo "bar")) '(foo "fraw")) '#hash((foo . "fraw")))
(check-equal? (attrs->hash '((foo "bar")) '(foo "fraw") 'foo "dog") '#hash((foo . "dog")))
(check-equal? (hash->attrs '#hash((foo . "bar")(hee . "haw"))) '((foo "bar")(hee "haw")))
(check-equal? (attr-ref '(p ((foo "bar"))) 'foo) "bar")
(check-equal? (attr-set '(p ((foo "bar"))) 'foo "fraw") '(p ((foo "fraw"))))
(check-true (attrs-have-key? '(p ((color "red")(shape "circle"))) 'color))
(check-true (attrs-have-key? '(p ((color "red")(shape "circle"))) "color"))
(check-false (attrs-have-key? '((color "red")(shape "circle")) 'nonexistent))
(check-equal? (merge-attrs 'foo "bar") '((foo "bar")))
(check-equal? (merge-attrs '(foo "bar")) '((foo "bar")))
(check-equal? (merge-attrs '((foo "bar"))) '((foo "bar")))
(check-equal? (merge-attrs "foo" 'bar) '((foo "bar")))
(check-equal? (merge-attrs "foo" "bar" "goo" "gar") '((foo "bar")(goo "gar")))
(check-equal? (merge-attrs (merge-attrs "foo" "bar" "goo" "gar") "hee" "haw")
'((foo "bar")(goo "gar")(hee "haw")))
(check-equal? (merge-attrs '((foo "bar")(goo "gar")) "foo" "haw") '((foo "haw")(goo "gar")))
(check-equal? (remove-attrs '(p ((foo "bar")) "hi")) '(p "hi"))
(check-equal? (remove-attrs '(p ((foo "bar")) "hi" (p ((foo "bar")) "hi"))) '(p "hi" (p "hi")))
(check-equal? (map-elements (λ(x) (if (string? x) "boing" x))
'(p "foo" "bar" (em "square")))
'(p "boing" "boing" (em "boing")))
(define split-this-tx '(root (meta "foo" "bar") "hello" "world" (meta "foo2" "bar2")
(em "goodnight" "moon" (meta "foo3" "bar3"))))
(check-equal? (call-with-values (λ() (splitf-txexpr split-this-tx (λ(x) (and (txexpr? x) (equal? 'meta (car x)))))) list)
(list '(root "hello" "world" (em "goodnight" "moon")) '((meta "foo" "bar") (meta "foo2" "bar2") (meta "foo3" "bar3"))))

@ -0,0 +1,328 @@
#lang racket/base
(require racket/match sugar/define sugar/list sugar/coerce
racket/string racket/list
xml
"private/define-provide-safe-match.rkt"
(for-syntax racket/base syntax/parse))
(provide cdata? cdata valid-char? xexpr->string xexpr? comment comment?) ; from xml
(provide empty) ; from racket/list
;; Section 2.2 of XML 1.1
;; (XML 1.0 is slightly different and more restrictive)
;; make private version of my-valid-char to get consistent results with Racket 6.0
(define (my-valid-char? i)
(and (exact-nonnegative-integer? i)
(or (<= #x1 i #xD7FF)
(<= #xE000 i #xFFFD)
(<= #x10000 i #x10FFFF))))
(define (my-xexpr? x)
(or (my-valid-char? x) (xexpr? x) (txexpr? x)))
(define+provide+safe (txexpr? x [allow-long #t])
predicate/c
(match x
[(cons (? txexpr-tag?) rest)
(=> resume)
(let loop ([rest rest])
(match rest
[(list (? my-xexpr?) ...) #true]
[(list (? txexpr-attrs?) elems ...) #:when allow-long (loop elems)]
[_ (resume)]))]
[_ #false]))
(define+provide+safe (txexpr-short? x)
predicate/c
(txexpr? x #false))
(define+provide+safe (txexpr-tag? x)
predicate/c
(symbol? x))
(define+provide+safe (txexpr-attr? x)
predicate/c
(match x
[(list (? txexpr-attr-key?) (? txexpr-attr-value?)) #true]
[_ #false]))
(define+provide+safe (txexpr-element? x)
predicate/c
(my-xexpr? x))
(define+provide+safe (txexpr-attr-key? x)
predicate/c
(symbol? x))
(define+provide+safe (can-be-txexpr-attr-key? x)
predicate/c
(symbolish? x))
(define+provide+safe (txexpr-attr-value? x)
predicate/c
(string? x))
(define+provide+safe (can-be-txexpr-attr-value? x)
predicate/c
(stringish? x))
(define-syntax-rule (define-plural plural-id pred)
(define+provide+safe (plural-id x)
predicate/c
(match x
[(list (? pred) (... ...)) #true]
[_ #false])))
(define-plural txexpr-tags? txexpr-tag?)
(define-plural txexpr-attrs? txexpr-attr?)
(define-plural txexpr-elements? txexpr-element?)
(define-plural txexpr-attr-values? txexpr-attr-value?)
(define-plural list-of-can-be-txexpr-attrs? can-be-txexpr-attrs?)
(define+provide+safe (can-be-txexpr-attrs? x)
predicate/c
(or (can-be-txexpr-attr-key? x)
(can-be-txexpr-attr-value? x)
(txexpr-attr? x)
(txexpr-attrs? x)))
(define (validate-txexpr-attrs tx)
(andmap
(lambda (attr)
(unless (and (list? attr) (eq? 2 (length attr)))
(txexpr-error "attribute" "is not a list of the form '(symbol \"string\")" attr tx))
(unless (symbol? (first attr))
(txexpr-error "attribute key" "is not a symbol" (first attr) tx))
(unless (string? (second attr))
(txexpr-error "attribute value" "is not a string" (second attr) tx))
#t)
(second tx)))
(define (validate-txexpr-elements elems tx)
(andmap
(lambda (e)
(cond
[(or (string? e) (symbol? e) (my-valid-char? e) (cdata? e) (comment? e)) #t]
[(and (list? e) (symbol? (first e)))
(validate-txexpr e)]
[else (txexpr-error "element" "not a valid element (= txexpr, string, symbol, XML char, cdata, or comment)" e tx)]))
elems))
(define (txexpr-error noun has-problem bad tx)
(raise-arguments-error 'validate-txexpr (format "~a ~a" noun has-problem) noun bad "in" tx))
;; is it a named x-expression?
;; Restricting to primitive predicates allows for more specific (helpful) errors
(define+provide+safe (validate-txexpr x)
(any/c . -> . txexpr?)
(unless (list? x) (raise-argument-error 'validate-txexpr "tagged X-expression" x))
(match x
[(list* tag _) #:when (not (symbol? tag))
(txexpr-error "tag" "must be a symbol" tag x)]
[(list* tag (or (? null?) (list (? list?) _ ...)) elems)
(and (validate-txexpr-attrs x) (validate-txexpr-elements elems x) x)]
[(list* tag elems) (and (validate-txexpr-elements elems x) x)]))
(define (txexpr-unsafe tag attrs elements)
(cons tag (match attrs
[(== empty) elements]
[_ (cons attrs elements)])))
(define (txexpr-base func-name tag attrs elements)
(unless (txexpr-tag? tag)
(raise-argument-error func-name "txexpr-tag?" tag))
(unless (txexpr-attrs? attrs)
(raise-argument-error func-name "txexpr-attrs?" attrs))
(unless (txexpr-elements? elements)
(raise-argument-error func-name "txexpr-elements?" elements))
(txexpr-unsafe tag attrs elements))
(define+provide+safe+match (txexpr tag [attrs null] [elements null])
((txexpr-tag?) (txexpr-attrs? txexpr-elements?) . ->* . txexpr?)
(txexpr-base 'txexpr tag attrs elements)
#:match-expander
(syntax-parser
[(_ tag-pat:expr
{~optional attrs-pat:expr #:defaults ([attrs-pat #'_])}
{~optional elements-pat:expr #:defaults ([elements-pat #'_])})
#'(? txexpr? (app txexpr->values tag-pat attrs-pat elements-pat))]))
(define+provide+safe (txexpr* tag [attrs null] . elements)
((txexpr-tag?) (txexpr-attrs?) #:rest txexpr-elements? . ->* . txexpr?)
(txexpr-base 'txexpr* tag attrs elements))
(define make-txexpr txexpr) ; for backward compatability
(provide+safe make-txexpr)
(define+provide+safe (txexpr->values x)
(txexpr? . -> . (values txexpr-tag? txexpr-attrs? txexpr-elements?))
(match x
[(? txexpr-short?) (values (car x) '() (cdr x))]
[_ (values (car x) (cadr x) (cddr x))]))
(define+provide+safe (txexpr->list x)
(txexpr? . -> . list?)
(call-with-values (λ () (txexpr->values x)) list))
;; convenience functions to retrieve only one part of txexpr
(define+provide+safe (get-tag x)
(txexpr? . -> . txexpr-tag?)
(car x))
(define+provide+safe (get-attrs x)
(txexpr? . -> . txexpr-attrs?)
(define-values (tag attrs elements) (txexpr->values x))
attrs)
(define+provide+safe (get-elements x)
(txexpr? . -> . txexpr-elements?)
(define-values (tag attrs elements) (txexpr->values x))
elements)
;; helpers. we are getting a string or symbol
(define+provide+safe (->txexpr-attr-key x)
(can-be-txexpr-attr-key? . -> . txexpr-attr-key?)
(unless (can-be-txexpr-attr-key? x)
(raise-argument-error '->txexpr-attr-key "can-be-txexpr-attr-key?" x))
(->symbol x))
(define+provide+safe (->txexpr-attr-value x)
(can-be-txexpr-attr-value? . -> . txexpr-attr-value?)
(unless (can-be-txexpr-attr-value? x)
(raise-argument-error '->txexpr-attr-value "can-be-txexpr-attr-value?" x))
(->string x))
(define (sublist->attr sublist)
(match sublist
[(list key value) (list (->txexpr-attr-key key) (->txexpr-attr-value value))]))
(define+provide+safe (attrs->hash #:hash-style? [hash-style-priority #f] . items-in)
(() (#:hash-style? boolean?) #:rest (listof can-be-txexpr-attrs?) . ->* . hash-eq?)
;; can be liberal with input because they're all just nested key/value pairs
;; but still need this function to make sure that 'foo and "foo" are treated as the same hash key
(define items (flatten items-in))
(unless (even? (length items))
(raise-argument-error 'attrs->hash "argument list of even length" (length items-in)))
;; hasheq loop will overwrite earlier values with later.
;; but earlier attributes need priority (see https://www.w3.org/TR/xml/#attdecls)
;; thus reverse the pairs.
;; priority-inverted will defeat this assumption, and allow later attributes to overwrite earlier.
(for/hasheq ([sublist (in-list ((if hash-style-priority
values
reverse) (slice-at items 2)))])
(apply values (sublist->attr sublist))))
(define+provide+safe (hash->attrs attr-hash)
(hash? . -> . txexpr-attrs?)
(match (hash->list attr-hash)
[(list (cons ks vs) ...) (map list ks vs)]))
(define+provide+safe (attrs-have-key? x key)
((or/c txexpr-attrs? txexpr?) can-be-txexpr-attr-key? . -> . boolean?)
(match x
[(? txexpr? tx) (and (attr-ref tx key #false) #true)]
[_ (attrs-have-key? (txexpr-unsafe '_ x null) key)]))
(define+provide+safe (attr-set tx key value)
(txexpr? can-be-txexpr-attr-key? can-be-txexpr-attr-value? . -> . txexpr?)
(attr-set* tx key value))
(define+provide+safe (attr-set* tx . kvs)
((txexpr?) #:rest (listof (or/c can-be-txexpr-attr-key? can-be-txexpr-attr-value?)) . ->* . txexpr?)
;; unlike others, this uses hash operations to guarantee that your attr-set
;; is the only one remaining.
(unless (even? (length kvs))
(raise-argument-error 'attr-set* "even number of arguments" kvs))
(define new-attrs (hash->attrs
(apply hash-set* (attrs->hash (get-attrs tx))
(append-map sublist->attr (slice-at kvs 2)))))
(txexpr-base 'attr-set* (get-tag tx) new-attrs (get-elements tx)))
(define+provide+safe (attr-join tx key value)
(txexpr? can-be-txexpr-attr-key? can-be-txexpr-attr-value? . -> . txexpr?)
(define starting-values (string-split (attr-ref tx key "")))
(attr-set tx key (string-join (append starting-values (list (->txexpr-attr-value value))) " ")))
(define no-failure-result (gensym)) ; failure-result might be #false
(define+provide+safe (attr-ref attrs-arg key [failure-result no-failure-result])
(((or/c txexpr? txexpr-attrs?) can-be-txexpr-attr-key?) (any/c) . ->* . any)
(match (assq (->txexpr-attr-key key) (match attrs-arg
[(? txexpr? tx) (get-attrs tx)]
[attrs attrs]))
[(list _ value) value]
[_ (match failure-result
[(? procedure?) (failure-result)]
[(== no-failure-result) (raise-argument-error 'attr-ref "key that exists in attr list" key)]
[_ failure-result])]))
(define+provide+safe (remove-attrs x)
(txexpr? . -> . txexpr?)
(let loop ([x x])
(if (txexpr? x)
(let-values ([(tag attrs elements) (txexpr->values x)])
(txexpr-unsafe tag null (map loop elements)))
x)))
(define+provide+safe (map-elements proc x)
(procedure? txexpr? . -> . txexpr?)
(let loop ([x x])
(proc (if (txexpr? x)
(let-values ([(tag attrs elements) (txexpr->values x)])
(txexpr-unsafe tag attrs (map loop elements)))
x))))
;; function to split tag out of txexpr
(define+provide+safe (splitf-txexpr tx pred [proc (λ (x) #f)])
((txexpr? procedure?) (procedure?) . ->* . (values txexpr? txexpr-elements?))
(unless (txexpr? tx)
(raise-argument-error 'splitf-txexpr "txexpr?" tx))
(define matches null)
(define (extract! x)
(match x
[(? pred)
(set! matches (cons x matches))
(proc x)]
[(? txexpr?) (let-values ([(tag attrs elements) (txexpr->values x)])
(txexpr-unsafe tag attrs (filter values (map extract! elements))))]
[_ x]))
(define tx-extracted (extract! tx)) ;; do this first to fill matches
(values tx-extracted (reverse matches)))
(define+provide+safe (findf*-txexpr tx pred)
(txexpr? procedure? . -> . (or/c #f txexpr-elements?))
(match/values (splitf-txexpr tx pred)
[(_ (? pair? matches)) matches]
[(_ _) #false]))
(define+provide+safe (findf-txexpr tx pred)
(txexpr? procedure? . -> . (or/c #f txexpr-element?))
(match (findf*-txexpr tx pred)
[(cons match _) match]
[_ #false]))
;; don't use "![CDATA[...]]" wrapper in HTML, it's not consistent with the spec
(define (->cdata x) (if (string? x) (cdata #f #f x) x))
;; but treat CDATA strings correctly anyhow, because that's friendly
(define (cdata-string? x)
(and (string? x) (regexp-match #rx"^<!\\[CDATA\\[.*\\]\\]>$" x) #true))
(define comment-pattern #rx"^<!--(.*?)-->$")
(define (string->comment x)
(match (regexp-match comment-pattern x)
[(list _ comment-payload) (comment comment-payload)]
[_ #false]))
(define+provide+safe (xexpr->html x)
(xexpr? . -> . string?)
(xexpr->string
(let loop ([x x])
(cond
[(txexpr? x)
(define-values (tag attrs elements) (txexpr->values x))
(define proc (if (memq tag '(script style)) ->cdata loop))
;; a little faster than `txexpr` since we know the pieces are valid
(txexpr-unsafe tag attrs (map proc elements))]
[(cdata-string? x) (->cdata x)]
[(and (string? x) (string->comment x))]
[else x]))))

@ -0,0 +1,39 @@
#lang racket/base
(require sugar/define racket/match "base.rkt" rackunit)
(define (stringify-attr attr)
(match attr
[(list key val) (string-append (symbol->string key) val)]))
(define (sort-attrs x)
(match x
[(? txexpr?)
(let-values ([(tag attr elements) (txexpr->values x)])
(txexpr tag (sort attr #:key stringify-attr #:cache-keys? #t string<?) (map sort-attrs elements)))]
[_ x]))
(define (txexprs-equal? tx1 tx2)
;; txexprs are deemed equal if they differ only in the ordering of attributes.
;; therefore, to check them, 1) sort their attributes, 2) straight list comparison.
;; use letrec because `define-simple-check` wants an expression in <=6.2
;; `stringify-attr` is needed because comparing attr keys won't work if there are two attrs with same key.
;; so the whole attr is converted into a single string for sorting, which lets the attr value act as a tiebreaker.
;; it doesn't matter that this sort may not be correct (in the sense of a desirable ordering)
;; it just needs to be stable (e.g., a certain set of attrs will always sort the same way)
(equal? (sort-attrs tx1) (sort-attrs tx2)))
(define+provide+safe (attrs-equal? x1 x2)
((or/c txexpr-attrs? txexpr?) (or/c txexpr-attrs? txexpr?) . -> . boolean?)
(apply txexprs-equal? (map (λ (x) `(_ ,(if (txexpr-attrs? x) x (get-attrs x)))) (list x1 x2))))
(provide+safe check-txexprs-equal?)
(define-simple-check (check-txexprs-equal? tx1 tx2)
(txexprs-equal? tx1 tx2))
(module+ test
(check-txexprs-equal? '(p ((b "foo")(a "bar")) (span ((d "foo")(c "bar"))))
'(p ((a "bar")(b "foo")) (span ((c "bar")(d "foo")))))
;; two attrs with same key
(check-txexprs-equal? '(p ((a "foo")(a "bar")))
'(p ((a "bar")(a "foo")))))

@ -0,0 +1,4 @@
#lang info
(define scribblings '(("scribblings/txexpr.scrbl" ())))
(define compile-omit-paths '("test/tests.rkt"))

@ -0,0 +1,14 @@
#lang racket/base
(define-syntax-rule (r+p MODNAME ...)
(begin
(begin
(require MODNAME)
(provide (all-from-out MODNAME))
(module+ safe
(require (submod MODNAME safe))
(provide (all-from-out (submod MODNAME safe))))) ...))
(r+p "base.rkt"
"stx.rkt"
"check.rkt")

@ -0,0 +1,43 @@
#lang racket/base
(provide txexpr?/recur
txexpr->values/attrs?)
(require racket/list)
;; A [TXcontainer T A E] is one of:
;; - (List* T A (Listof E))
;; - (Lxst* T (Listof E))
;; Where A and E are disjoint.
;; txexpr?/recur :
;; Any
;; [Any -> Bool : T]
;; [Any -> Bool : #:+ (and A (! E)) #:- (! A)]
;; [Any -> Bool : #:+ (and E (! A)) #:- (! E)]
;; ->
;; Bool
;; : [TXcontainer T A E]
;; the attrs? predicate and the element? predicate should be disjoint
(define (txexpr?/recur v tag? attrs? element?)
(and (list? v)
(not (empty? v))
(tag? (first v))
(cond [(and (not (empty? (rest v)))
(attrs? (second v)))
(andmap element? (rest (rest v)))]
[else
(andmap element? (rest v))])))
;; txexpr->values/attrs? :
;; [TXcontainer T A E]
;; [Any -> Bool : #:+ (and A (! E)) #:- (! A)]
;; ->
;; (values T A (Listof E))
(define (txexpr->values/attrs? tx attrs?)
(cond [(and (not (empty? (rest tx)))
(attrs? (second tx)))
(values (first tx) (second tx) (rest (rest tx)))]
[else
(values (first tx) '() (rest tx))]))

@ -0,0 +1,82 @@
#lang racket/base
(provide define+provide+safe+match)
(require racket/match
(for-syntax racket/base
racket/syntax
syntax/parse
syntax/stx
version/utils))
;; (define+provide+safe+match name-id
;; contract-expr
;; value-expr
;; #:match-expander
;; match-transformer-expr)
;;
;; (define+provide+safe+match (head . args)
;; contract-expr
;; value-body-expr
;; ...+
;; #:match-expander
;; match-transformer-expr)
(begin-for-syntax
;; Identifier -> [Syntax -> Syntax]
(define ((variable-like-transformer id) stx)
(cond
[(identifier? stx)
; id, but with the source location of stx
(datum->syntax id (syntax-e id) stx id)]
[(stx-pair? stx)
(datum->syntax stx (cons id (stx-cdr stx)) stx stx)])))
(define-syntax define+provide+safe+match
(λ (stx)
(syntax-parse stx
[(d (head . args)
contract:expr
value-body:expr ...+
#:match-expander match-transformer:expr)
#:with fn-expr (syntax/loc stx (λ args value-body ...))
(syntax/loc stx
(d head contract fn-expr #:match-expander match-transformer))]
[(_ name:id
contract:expr
value:expr
#:match-expander match-transformer:expr)
#:with internal-name (generate-temporary #'name)
#:with contract-name (generate-temporary #'name)
#:with make-name-match-transformer (generate-temporary #'name)
#:with [name-for-blame ...]
(cond [(version<=? "6.8" (version)) #'[#:name-for-blame name]]
[else #'[]])
#'(begin
(define internal-name (let ([name value]) name))
(begin-for-syntax
(define (make-name-match-transformer name)
(with-syntax ([name name]) match-transformer)))
(define-match-expander name
(make-name-match-transformer (quote-syntax internal-name))
(variable-like-transformer (quote-syntax internal-name)))
(provide name)
(module+ safe
(require racket/contract/base)
(define-module-boundary-contract contract-name internal-name contract
name-for-blame ...)
(define-match-expander name
(make-name-match-transformer (quote-syntax contract-name))
(variable-like-transformer (quote-syntax contract-name)))
(provide name)))])))

@ -0,0 +1,688 @@
#lang scribble/manual
@; for documentation purposes, use the xexpr? from xml.
@; the one in txexpr is just to patch over an issue with
@; `valid-char?` in Racket 6.
@(require scribble/eval
(for-label racket txexpr txexpr/stx xml rackunit))
@(define my-eval (make-base-eval))
@(my-eval `(require racket/match txexpr xml rackunit))
@title{txexpr: Tagged X-expressions}
@author[(author+email "Matthew Butterick" "mb@mbtype.com")]
@defmodule[#:multi (txexpr (submod txexpr safe))]
A set of small but handy functions for improving the readability and reliability of programs that operate on tagged X-expressions (for short, @italic{txexpr}s).
@section{Installation}
At the command line:
@verbatim{raco pkg install txexpr}
After that, you can update the package from the command line:
@verbatim{raco pkg update txexpr}
@section{Importing the module}
The module can be invoked two ways: fast or safe.
Fast mode is the default, which you get by importing the module in the usual way: @code{(require txexpr)}.
Safe mode enables the function contracts documented below. Use safe mode by importing the module as @code{(require (submod txexpr safe))}.
@section[#:tag "what-is-a-txexpr"]{Whats a tagged X-expression (aka txexpr)?}
It's an X-expression with the following grammar:
@racketgrammar*[
#:literals (cons list symbol? string? xexpr?)
[txexpr (list tag (list attr ...) element ...)
(cons tag (list element ...))]
[tag symbol?]
[attr (list key value)]
[key symbol?]
[value string?]
[element xexpr?]
]
A tagged X-expression — @italic{txexpr} for short — is a list with a symbol in the first position — the @italic{tag} — followed by a series of @italic{elements}, which are other X-expressions. Optionally, a txexpr can have a list of @italic{attributes} in the second position.
@examples[#:eval my-eval
(txexpr? '(span "Brennan" "Dale"))
(txexpr? '(span "Brennan" (em "Richard") "Dale"))
(txexpr? '(span ((class "hidden")(id "names")) "Brennan" "Dale"))
(txexpr? '(span lt gt amp))
(txexpr? '("We really" "should have" "a tag"))
(txexpr? '(span ((class not-quoted)) "Brennan"))
(txexpr? '(span (class "hidden") "Brennan" "Dale"))
]
The last one is a common mistake. Because the keyvalue pair is not enclosed in a @tech[#:doc '(lib "scribblings/guide/guide.scrbl")]{list}, it's interpreted as a nested txexpr within the first txexpr, as you may not find out until you try to read its attributes:
@examples[#:eval my-eval
(get-attrs '(span (class "hidden") "Brennan" "Dale"))
(get-elements '(span (class "hidden") "Brennan" "Dale"))
]
Tagged X-expressions are most commonly found in HTML & XML documents. Though the notation is different in Racket, the data structure is identical:
@examples[#:eval my-eval
(xexpr->string '(span ((id "names")) "Brennan" (em "Richard") "Dale"))
(string->xexpr "<span id=\"names\">Brennan<em>Richard</em>Dale</span>")
]
After converting to and from HTML, we get back the original X-expression. Well, almost. Per its usual practice, @racket[string->xexpr] added an empty attribute list after @racket[em]. This is benign — an empty attribute list can be omitted with no change in meaning, or vice versa.
@section{Why not just use @exec{match}, @exec{quasiquote}, and so on?}
If you prefer those, please do. But I've found two benefits to using module functions:
@bold{Readability.} In code that already has a lot of matching and quasiquoting going on, these functions make it easy to see where & how txexprs are being used.
@bold{Reliability.} Because txexprs come in two close but not quite equal forms, careful coders will always have to take both cases into account.
The programming is trivial, but the annoyance is real.
@section{Predicates}
@deftogether[(
@defproc[
(txexpr?
[v any/c])
boolean?]
@defproc[
(txexpr-tag?
[v any/c])
boolean?]
@defproc[
(txexpr-attr?
[v any/c])
boolean?]
@defproc[
(txexpr-attr-key?
[v any/c])
boolean?]
@defproc[
(txexpr-attr-value?
[v any/c])
boolean?]
@defproc[
(txexpr-element?
[v any/c])
boolean?]
)]
Predicates for @racket[_txexpr]s that implement this grammar:
@racketgrammar*[
#:literals (cons list symbol? string? xexpr?)
[txexpr (list tag (list attr ...) element ...)
(cons tag (list element ...))]
[tag symbol?]
[attr (list key value)]
[key symbol?]
[value string?]
[element xexpr?]
]
@deftogether[(
@defproc[
(txexpr-tags?
[v any/c])
boolean?]
@defproc[
(txexpr-attrs?
[v any/c])
boolean?]
@defproc[
(txexpr-elements?
[v any/c])
boolean?]
)]
Predicates equivalent to a list of @code{txexpr-tag?}, @code{txexpr-attr?}, or @code{txexpr-element?}, respectively.
@deftogether[(
@defproc[
(can-be-txexpr-attr-key?
[v any/c])
boolean?]
@defproc[
(can-be-txexpr-attr-value?
[v any/c])
boolean?]
)]
Predicates for input arguments that can be trivially converted to an attribute @racket[_key] or @racket[_value] with the associated conversion functions.
@examples[#:eval my-eval
(can-be-txexpr-attr-key? 'symbol)
(can-be-txexpr-attr-key? "string-val")
(can-be-txexpr-attr-key? (list 1 2 3))
(can-be-txexpr-attr-value? 'symbol)
(can-be-txexpr-attr-value? "string-val")
(can-be-txexpr-attr-value? (list 1 2 3))
]
@defproc[
(can-be-txexpr-attrs?
[v any/c])
boolean?]
Predicate for functions that handle @racket[_txexpr-attrs]. Covers values that are easily converted into pairs of @racket[_attr-key] and @racket[_attr-value]. Namely: single @racket[_xexpr-attr]s, lists of @racket[_xexpr-attr]s (i.e., what you get from @racket[get-attrs]), or interleaved symbols and strings (each pair will be concatenated into a single @racket[_xexpr-attr]).
@defproc[
(validate-txexpr
[possible-txexpr any/c])
txexpr?]
Like @racket[txexpr?], but raise a descriptive error pinpointing the first problem encountered if @racket[_possible-txexpr] is invalid, and otherwise return @racket[_possible-txexpr] itself.
@examples[#:eval my-eval
(validate-txexpr 'root)
(validate-txexpr '(root))
(validate-txexpr '(root ((id "top")(class 42))))
(validate-txexpr '(root ((id "top")(class "42"))))
(validate-txexpr '(root ((id "top")(class "42")) ("hi")))
(validate-txexpr '(root ((id "top")(class "42")) "hi"))
(validate-txexpr '(root (p "Hello " (span [[class "inner"]] (1 2 3)))))
(validate-txexpr `(root (p "Look out" (span ,(void)) (1 2 3))))
]
@section{Making & breaking}
@defproc[
(txexpr
[tag txexpr-tag?]
[attrs txexpr-attrs? @empty]
[elements txexpr-elements? @empty])
txexpr?]
Assemble a @racket[_txexpr] from its parts. If you don't have attributes, but you do have elements, you'll need to pass @racket[empty] (or @racket[null] or @racket['()]) as the second argument. Note that unlike @racket[xml->xexpr], if the attribute list is empty, it's not included in the resulting expression.
@examples[#:eval my-eval
(txexpr 'div)
(txexpr 'div '() '("Hello" (p "World")))
(txexpr 'div '((id "top")))
(txexpr 'div '((id "top")) '("Hello" (p "World")))
(define tx '(div ((id "top")) "Hello" (p "World")))
(txexpr (get-tag tx)
(get-attrs tx) (get-elements tx))
]
The @racket[txexpr] form can also be used as a match pattern:
@examples[#:eval my-eval
(match '(div)
[(txexpr tag attrs elems)
(values tag attrs elems)])
(match '(div "Hello" (p "World"))
[(txexpr tag attrs elems)
(values tag attrs elems)])
(match '(div "Hello" (p "World"))
[(txexpr 'div attrs1 (list elems1 ... (txexpr 'p attrs2 elems2)))
(values attrs1 elems1 attrs2 elems2)])
(match '(div ((id "top")) "Hello" (p "World"))
[(txexpr 'div attrs1 (list elems1 ... (txexpr 'p attrs2 elems2)))
(values attrs1 elems1 attrs2 elems2)])
]
@defproc[
(txexpr*
[tag txexpr-tag?]
[attrs txexpr-attrs? @empty]
[element txexpr-element?] ...)
txexpr?]
Like @racket[txexpr], but takes an indefinite number of @racket[_element] arguments, which together are treated as the list of elements for the resulting @racket[_txexpr]. A notational convenience.
@examples[#:eval my-eval
(txexpr* 'div)
(txexpr* 'div '() "Hello" '(p "World"))
(txexpr* 'div '((id "top")))
(txexpr* 'div '((id "top")) "Hello" '(p "World"))
(define tx '(div ((id "top")) "Hello" (p "World")))
(apply txexpr* (get-tag tx)
(get-attrs tx) (get-elements tx))
]
@deftogether[(
@defproc[
(get-tag
[tx txexpr?])
txexpr-tag?]
@defproc[
(get-attrs
[tx txexpr?])
txexpr-attr?]
@defproc[
(get-elements
[tx txexpr?])
(listof txexpr-element?)]
)]
Accessor functions for the individual pieces of a @racket[_txexpr].
@examples[#:eval my-eval
(get-tag '(div ((id "top")) "Hello" (p "World")))
(get-attrs '(div ((id "top")) "Hello" (p "World")))
(get-elements '(div ((id "top")) "Hello" (p "World")))
]
@deftogether[(
@defproc[
(txexpr->values
[tx txexpr?])
(values txexpr-tag? txexpr-attrs? txexpr-elements?)]
@defproc[
(txexpr->list
[tx txexpr?])
(list txexpr-tag?
txexpr-attrs?
txexpr-elements?)]
)]
Dissolve a @racket[_txexpr] into its components. @racket[txexpr->values] returns the components as multiple values; @racket[txexpr->list] returns them in a list.
@examples[#:eval my-eval
(txexpr->values '(div))
(txexpr->values '(div "Hello" (p "World")))
(txexpr->values '(div ((id "top")) "Hello" (p "World")))
(txexpr->list '(div))
(txexpr->list '(div "Hello" (p "World")))
(txexpr->list '(div ((id "top")) "Hello" (p "World")))
]
@section{Attributes}
@deftogether[(
@defproc[
(attrs->hash
[#:hash-style? hash-style-priority boolean? #f]
[x can-be-txexpr-attrs?] ...)
hash-eq?]
@defproc[
(hash->attrs
[h hash?])
txexpr-attrs?]
)]
Convert @racket[_attrs] to an immutable hash, and back again. Following the convention specified for @link["https://www.w3.org/TR/xml/#attdecls"]{XML parsers}, the @italic{first} appearance of an attribute name binds the value — later attributes with the same name are ignored. If you prefer the typical @racket[hash] behavior where later values override earlier ones, set @racket[#:hash-style?] to @racket[#t].
@examples[#:eval my-eval
(define tx '(div ((id "top")(class "red")) "Hello" (p "World")))
(attrs->hash (get-attrs tx))
(hash->attrs '#hasheq((class . "red") (id . "top")))
(attrs->hash '((color "blue")(color "green")))
(attrs->hash #:hash-style? #t '((color "blue")(color "green")))
]
@defproc[
(attrs-have-key?
[attrs (or/c txexpr-attrs? txexpr?)]
[key can-be-txexpr-attr-key?])
boolean?]
Return @racket[#t] if the @racket[_attrs] contain a value for the given @racket[_key], @racket[#f] otherwise.
@examples[#:eval my-eval
(define tx '(div ((id "top")(class "red")) "Hello" (p "World")))
(attrs-have-key? tx 'id)
(attrs-have-key? tx 'grackle)
]
@defproc[
(attrs-equal?
[attrs (or/c txexpr-attrs? txexpr?)]
[other-attrs (or/c txexpr-attrs? txexpr?)])
boolean?]
Return @racket[#t] if @racket[_attrs] and @racket[_other-attrs] contain the same keys and values, @racket[#f] otherwise. The order of attributes is irrelevant. (If order matters to you, use good old @racket[equal?] instead.)
@examples[#:eval my-eval
(define tx1 '(div ((id "top")(class "red")) "Hello"))
(define tx2 '(p ((class "red")(id "top")) "Hello"))
(define tx3 '(p ((id "bottom")(class "red")) "Hello"))
(attrs-equal? tx1 tx2)
(attrs-equal? tx1 tx3)
(equal? tx1 tx2)
(equal? tx1 tx3)
]
@defproc[
(attr-ref
[attrs (or/c txexpr-attrs? txexpr?)]
[key can-be-txexpr-attr-key?]
[failure-result any/c (λ _ (raise (make-exn:fail:contract ....)))
])
any]
Given a @racket[_key], return the corresponding @racket[_value] from @racket[_attrs]. By default, asking for a nonexistent key produces an error. But if a value or procedure is provided as the @racket[_failure-result], evaluate and return that instead.
@examples[#:eval my-eval
(define tx '(div ((id "top")(class "red")) "Hello" (p "World")))
(attr-ref tx 'class)
(attr-ref tx 'id)
(attr-ref tx 'nonexistent-key)
(attr-ref tx 'nonexistent-key "forty-two")
(attr-ref tx 'nonexistent-key (λ _ (* 6 7)))
(define attrs '((id "top")(class "red")))
(attr-ref attrs 'class)
(attr-ref attrs 'id)
(attr-ref attrs 'nonexistent-key)
]
@deftogether[(
@defproc[
(attr-set
[tx txexpr?]
[key can-be-txexpr-attr-key?]
[value can-be-txexpr-attr-value?])
txexpr?]
@defproc[
(attr-set*
[tx txexpr?]
[key can-be-txexpr-attr-key?]
[value can-be-txexpr-attr-value?] ... ... )
txexpr?]
)]
Set the value of attribute @racket[_key] to @racket[_value] in @racket[_txexpr]. Return the updated @racket[_txexpr]. Duplicate attributes, if they exist, are resolved using @racket[attrs->hash]. @racket[attr-set] only accepts one key and one value; @racket[attr-set*] accepts any number.
@examples[#:eval my-eval
(define tx '(div ((class "red")(id "top")) "Hello" (p "World")))
(attr-set tx 'id "bottom")
(attr-set tx 'class "blue")
(attr-set (attr-set tx 'id "bottom") 'class "blue")
(define tx '(div "Hello"))
(attr-set* tx 'id "bottom" 'class "blue")
]
@defproc[
(attr-join
[tx txexpr?]
[key can-be-txexpr-attr-key?]
[value can-be-txexpr-attr-value?])
txexpr?]
Given a @racket[_txexpr], append attribute @racket[_key] with @racket[_value]. Return the updated @racket[_txexpr]. If @racket[_key] doesn't already exist, then add a new attribute (i.e., behave like @racket[attr-set]).
@examples[#:eval my-eval
(define tx '(div ((class "red")) "Hello"))
(attr-join tx 'class "small")
(attr-join tx 'klass "small")
]
@defproc[
(remove-attrs
[tx txexpr?])
txexpr?]
Recursively remove all attributes from @racket[_tx].
@examples[#:eval my-eval
(define tx '(div ((id "top")) "Hello" (p ((id "lower")) "World")))
(remove-attrs tx)
]
@section{Strange magic}
@defproc[
(map-elements
[proc procedure?]
[tx txexpr?])
txexpr?]
Recursively apply @racket[_proc] to all elements, leaving tags and attributes alone. Using plain @racket[map] will only process elements at the top level of @racket[_tx]. Usually that's not what you want.
@examples[#:eval my-eval
(define tx '(div "Hello!" (p "Welcome to" (strong "Mars"))))
(define upcaser (λ (x) (if (string? x) (string-upcase x) x)))
(map upcaser tx)
(map-elements upcaser tx)
]
In practice, most @racket[_txexpr-element]s are strings. But it's unwise to pass string-only procedures to @racket[map-elements], because an @racket[_txexpr-element] can be any kind of @racket[xexpr?], and an @racket[xexpr?] is not necessarily a string.
@examples[#:eval my-eval
(define tx '(p "Welcome to" (strong "Mars" amp "Sons")))
(map-elements string-upcase tx)
(define upcaser (λ (x) (if (string? x) (string-upcase x) x)))
(map-elements upcaser tx)
]
@defproc[
(splitf-txexpr
[tx txexpr?]
[pred procedure?]
[replace-proc procedure? (λ (x) #f)])
(values txexpr? (listof txexpr-element?))]
Recursively descend through @racket[_txexpr] and extract all elements that match @racket[_pred]. Returns two values: a @racket[_txexpr] with the matching elements removed, and the list of matching elements. Sort of esoteric, but I've needed it more than once, so here it is.
@examples[#:eval my-eval
(define tx '(div "Wonderful day" (meta "weather" "good") "for a walk"))
(define is-meta? (λ (x) (and (txexpr? x) (equal? 'meta (get-tag x)))))
(splitf-txexpr tx is-meta?)
]
Ordinarily, the result of the split operation is to remove the elements that match @racket[_pred]. But you can change this behavior with the optional @racket[_replace-proc] argument.
@examples[#:eval my-eval
(define tx '(div "Wonderful day" (meta "weather" "good") "for a walk"))
(define is-meta? (λ (x) (and (txexpr? x) (equal? 'meta (get-tag x)))))
(define replace-meta (λ (x) '(em "meta was here")))
(splitf-txexpr tx is-meta? replace-meta)
]
@deftogether[(
@defproc[
(findf-txexpr
[tx txexpr?]
[pred procedure?])
(or/c #f txexpr-element?)]
@defproc[
(findf*-txexpr
[tx txexpr?]
[pred procedure?])
(or/c #f (listof txexpr-element?))]
)]
Like @racket[splitf-txexpr], but only retrieve the elements that match @racket[_pred]. @racket[findf*-txexpr] retrieves all results; @racket[findf-txexpr] only the first. In both cases, if there are no matches, you get @racket[#f].
@examples[#:eval my-eval
(define tx '(div "Wonderful day" (meta "weather" "good")
"for a walk" (meta "dog" "Roxy")))
(define is-meta? (λ (x) (and (txexpr? x) (eq? 'meta (get-tag x)))))
(findf*-txexpr tx is-meta?)
(findf-txexpr tx is-meta?)
(define is-zimzam? (λ (x) (and (txexpr? x) (eq? 'zimzam (get-tag x)))))
(findf*-txexpr tx is-zimzam?)
(findf-txexpr tx is-zimzam?)
]
@section{HTML conversion}
@defproc[
(xexpr->html
[x xexpr?])
string?]
Convert @racket[_x] to an HTML string. Better than @racket[xexpr->string] because consistent with the HTML spec, it will skip the content of @code{script} or @code{style} blocks. For convenience, this function will take any X-expression, not just tagged X-expressions.
@examples[#:eval my-eval
(define tx '(root (script "3 > 2") "Why is 3 > 2?"))
(xexpr->string tx)
(xexpr->html tx)
(map xexpr->html (list "string" 'entity 65))
]
@section{Unit testing}
@defproc[
(check-txexprs-equal?
[tx1 txexpr?]
[tx2 txexpr?])
void?]
Designed to be used with @racketmodname[rackunit]. Check whether @racket[_tx1] and @racket[_tx2] are @racket[equal?] except for ordering of attributes (which ordinarily has no semantic significance). Return @racket[void] if so, otherwise raise a check failure.
@examples[#:eval my-eval
(define tx1 '(div ((attr-a "foo")(attr-z "bar"))))
(define tx2 '(div ((attr-z "bar")(attr-a "foo"))))
(parameterize ([current-check-handler (λ _ (display "not "))])
(display "txexprs are ")
(check-txexprs-equal? tx1 tx2)
(displayln "equal"))
]
If ordering of attributes is relevant to your test, then just use @racket[check-equal?] as usual.
@examples[#:eval my-eval
(define tx1 '(div ((attr-a "foo")(attr-z "bar"))))
(define tx2 '(div ((attr-z "bar")(attr-a "foo"))))
(parameterize ([current-check-handler (λ _ (display "not "))])
(display "txexprs are ")
(check-equal? tx1 tx2)
(displayln "equal"))
]
@section{Syntax Versions of X-expressions}
@(define stx-eval (make-base-eval))
@(stx-eval `(require txexpr txexpr/stx xml rackunit))
@defmodule[txexpr/stx]{
This module provides functions for destructuring TX-expressions
that might be wrapped in syntax objects.
}
@defproc[(stx-xexpr? [v any/c]) boolean?]{
A predicate for X-expressions that might be wrapped in syntax
(or have parts of them wrapped in syntax). It returns
@racket[#true] for values that would become normal X-expressions
with @racket[(syntax->datum (datum->syntax #f v))].
@examples[#:eval stx-eval
(stx-xexpr? "A leaf on the wind")
(stx-xexpr? #'"A leaf in a bin")
(stx-xexpr? '(div ((id "top")) "Hello" (p "World")))
(stx-xexpr? #'(div ((id "top")) "Hello" (p "World")))
(stx-xexpr? `(div ((id ,#'"top")) "Hello" ,#'(p "World")))
]}
@defproc[(stx-txexpr? [v any/c]) boolean?]{
A predicate for Tagged X-expressions that might be wrapped in
syntax. It returns @racket[#true] for values that become one
of these with @racket[(syntax->datum (datum->syntax #f v))]:
@racketgrammar*[
#:literals (list)
[txexpr (list tag attrs xexpr ...)
(list tag xexpr ...)]
]
@examples[#:eval stx-eval
(stx-txexpr? "A block at the top")
(stx-txexpr? '(div ((id "top")) "A block beneath a" (p "tag")))
(stx-txexpr? #'(div ((id "top")) "A block beneath a" (p "tag")))
(stx-txexpr? #'(div "A block beneath a" (p "tag")))
]}
@deftogether[[
@defproc[(stx-txexpr-tag? [v any/c]) boolean?]
@defproc[(stx-txexpr-attrs? [v any/c]) boolean?]
]]{
Predicates for sub-parts of TX-expressions that might be wrapped
in syntax. There return @racket[#true] for values that become
@racket[txexpr-tag?]s or @racket[txexpr-attrs?]s when unwrapped
with @racket[(syntax->datum (datum->syntax #f v))].
@examples[#:eval stx-eval
(stx-txexpr-tag? 'div)
(stx-txexpr-tag? #'div)
(stx-txexpr-tag? 'analogous)
(stx-txexpr-tag? #'analogous)
(stx-txexpr-attrs? '())
(stx-txexpr-attrs? #'())
(stx-txexpr-attrs? '((id "top") (style "color: blue")))
(stx-txexpr-attrs? #'((id "top") (style "color: blue")))
(stx-txexpr-attrs? `((id "top") (style ,#'"color: blue")))
]}
@deftogether[[
@defproc[(stx-txexpr-tag [tx stx-txexpr?]) stx-txexpr-tag?]
@defproc[(stx-txexpr-attrs [tx stx-txexpr?]) stx-txexpr-attrs?]
@defproc[(stx-txexpr-elements [tx stx-txexpr?]) (listof stx-txexpr?)]
]]{
Accessor functions for the tag, attributes, and elements of a
txexpr that might be wrapped in syntax. Note that these functions
work whether the input is wrapped in syntax or not, and that
the results may or may not be wrapped in syntax, depending on
whether the input was wrapped.
@examples[#:eval stx-eval
(define tx1 '(div ((id "top")) "Hello" (p "World")))
(define tx2 #'(div ((id "top")) "Hello" (p "World")))
(stx-txexpr-tag tx1)
(stx-txexpr-tag tx2)
(stx-txexpr-attrs tx1)
(stx-txexpr-attrs tx2)
(stx-txexpr-elements tx1)
(stx-txexpr-elements tx2)
]}
@deftogether[[
@defproc[(stx-txexpr->values [tx stx-txexpr?])
(values stx-txexpr-tag? stx-txexpr-attrs? (listof stx-txexpr?))]
@defproc[(stx-txexpr->list [tx stx-txexpr?])
(list/c stx-txexpr-tag? stx-txexpr-attrs? (listof stx-txexpr?))]
]]{
These functions break up a TX-expression into its components.
@racket[stx-txexpr->values] returns them as three values, and
@racket[stx-txexpr->list] returns them as a three-element list.
@examples[#:eval stx-eval
(stx-txexpr->values '(div))
(stx-txexpr->list '(div))
(stx-txexpr->values #'(div))
(stx-txexpr->values #'(div "Hello" (p "World")))
(stx-txexpr->values #'(div ((id "top")) "Hello" (p "World")))
(stx-txexpr->values `(div ((id "top")) "Hello" ,#'(p "World")))
]}
@section{License & source code}
This module is licensed under the LGPL.
Source repository at @link["http://github.com/mbutterick/txexpr"]{http://github.com/mbutterick/txexpr}. Suggestions & corrections welcome.

@ -0,0 +1,129 @@
#lang racket/base
(provide stx-xexpr?
stx-txexpr?
stx-txexpr-tag?
stx-txexpr-attrs?
stx-txexpr->values
stx-txexpr->list
stx-txexpr-tag
stx-txexpr-attrs
stx-txexpr-elements)
(require syntax/stx
xml
"base.rkt"
"private/container.rkt")
;; ---------------------------------------------------------
;; Data Definitions
;; A [Stx E] is one of:
;; - (Syntaxof E)
;; - E
;; A StxXexpr is a [Stx XexprE]
;; A StxTXexpr is a [Stx TXexprE]
;; A StxTag is a [Stx Symbol]
;; A StxAttrs is a (StxListof (StxList [Stx Symbol] [Stx String]))
;; A StxElements is a (StxListof StxXexpr)
;; A XexprE is one of:
;; - String
;; - TXexprE
;; - Symbol ; for example 'nbsp representing `&nbsp;`
;; - ValidChar ; for example #x20 representing `&#x20;`
;; - CData ; an instance of the `cdata` structure type from `xml`
;; - Misc ; an instance of the `comment` or `p-i` structure types
;; A TXexprE is one of:
;; - (list* StxTag StxAttrs StxElements)
;; - (list* StxTag StxElements)
;; The types `StxAttrs` and `StxXexpr` are disjoint, as they
;; need to be for this to be unambiguous.
;; ---------------------------------------------------------
;; Predicates
;; Any -> Bool
(define (stx-xexpr? v)
(stx-xexpr?/recur v stx-xexpr?))
;; Any -> Bool
(define (stx-txexpr? v)
(stx-txexpr?/recur v stx-xexpr?))
;; Any [Any -> Bool] -> Bool
(define (stx-xexpr?/recur v rec)
(cond
[(syntax? v) (stx-xexpr?/recur (syntax-e v) rec)]
[(pair? v) (stx-txexpr?/recur v rec)]
[else (xexpr?/recur v rec)]))
;; Any [Any -> Bool] -> Bool
;; the `rec` predicate should not overlap with `txexpr-attrs?`
(define (xexpr?/recur v rec)
(cond
[(pair? v) (txexpr?/recur v txexpr-tag? txexpr-attrs? rec)]
[(string? v) #true]
[(symbol? v) #true]
[(integer? v) (valid-char? v)]
[(cdata? v) #true]
[(comment? v) #true]
[(p-i? v) #true]
[else #false]))
;; Any [Any -> Bool] -> Bool
;; the `rec` predicate should not overlap with
;; `stx-txexpr-attrs?`
(define (stx-txexpr?/recur v rec)
;; Even if it's not stx, the cdr or cddr might be syntax.
;; This flattens it so that the cdd...r is always a pair or empty.
(define lst (stx->list v))
(and lst (txexpr?/recur lst stx-txexpr-tag? stx-txexpr-attrs? rec)))
;; Any -> Bool
(define (stx-txexpr-tag? v)
(cond
[(syntax? v) (txexpr-tag? (syntax-e v))]
[else (txexpr-tag? v)]))
;; Any -> Bool
(define (stx-txexpr-attrs? v)
(txexpr-attrs? (syntax->datum (datum->syntax #f v))))
;; ---------------------------------------------------------
;; Accessors
;; StxTxexpr -> (values StxTag StxAttrs StxElements)
(define (stx-txexpr->values v)
(txexpr->values/attrs? (stx->list v) stx-txexpr-attrs?))
;; StxTxexpr -> (List StxTag StxAttrs StxElements)
(define (stx-txexpr->list v)
(define-values [tag attrs elements] (stx-txexpr->values v))
(list tag attrs elements))
;; StxTxexpr -> StxTag
(define (stx-txexpr-tag v)
(define-values [tag attrs elements] (stx-txexpr->values v))
tag)
;; StxTxexpr -> StxAttrs
(define (stx-txexpr-attrs v)
(define-values [tag attrs elements] (stx-txexpr->values v))
attrs)
;; StxTxexpr -> StxElements
(define (stx-txexpr-elements v)
(define-values [tag attrs elements] (stx-txexpr->values v))
elements)
;; ---------------------------------------------------------
(module+ safe
(provide (all-defined-out)))

@ -0,0 +1,63 @@
#lang racket/base
(provide values->list
check-values=?
check/values)
(require rackunit
(for-syntax racket/base))
;; Takes an expression producing an unknown number of values
;; and wraps them all in a list.
(define-syntax-rule (values->list values-expr)
(call-with-values (λ () values-expr) list))
;; Checks that two expressions (each producing an unknown
;; number of values until evaluated) produce the same number
;; of values, and that the values are equal.
(define-syntax check-values=?
(lambda (stx)
(syntax-case stx []
[(_ actual-expr expected-expr)
(syntax/loc stx
(check/values check-equal? actual-expr expected-expr))])))
(define-syntax check/values
(lambda (stx)
(syntax-case stx []
[(_ check-form actual-expr expected-expr)
(syntax/loc stx
(check-form (vs actual-expr) (vs expected-expr)))])))
;; Takes an expression producing an unknown number of values
;; and wraps them in a "fake-values" structure that can be
;; compared with other fake-values structures for equality,
;; and can be printed to look like a call to `values`.
(define-syntax-rule (vs values-expr)
(fake-values (values->list values-expr)))
;; if make-constructor-style-printer from racket/struct exists,
;; this is it, and otherwise this is a cheap immitation.
(define make-constructor-style-printer
(with-handlers ([exn:fail:filesystem?
(λ (e)
(λ (get-head get-elems)
(λ (v out mode)
(define head (get-head v))
(define elems (get-elems v))
(fprintf out "(~a" head)
(for ([elem elems])
(fprintf out " ~v" elem))
(fprintf out ")"))))])
(dynamic-require 'racket/struct 'make-constructor-style-printer)))
(struct fake-values [list]
#:transparent
#:methods gen:custom-write
[(define write-proc
(make-constructor-style-printer
(lambda (self) 'values)
(lambda (self) (fake-values-list self))))])

@ -0,0 +1,16 @@
#lang racket/base
(require (submod "../main.rkt" safe))
(module+ test
(require rackunit))
(module+ test
(check-exn (regexp (string-append
"txexpr.*: contract violation\n"
" *expected: txexpr-tag\\?\n"
" *given: 4\n"
" *in: the 1st argument.*"
" *blaming: .*test/contract-tests.rkt"))
(λ () (txexpr 4)))
)

@ -0,0 +1,115 @@
#lang racket/base
(require rackunit "../stx.rkt" "check-values.rkt"
(for-syntax racket/base))
;; Works on fully wrapped, non-wrapped, and partially
;; wrapped values, and it checks that the the inputs
;; are wrapped in all the same places. It checks scopes,
;; but it does not check source location.
(define-binary-check (check-stx=? stx=? actual expected))
(define (stx=? a b)
(cond
[(and (identifier? a) (identifier? b))
(bound-identifier=? a b)]
[(and (syntax? a) (syntax? b))
(and (bound-identifier=? (datum->syntax a '||) (datum->syntax b '||))
(stx=? (syntax-e a) (syntax-e b)))]
[else
(equal?/recur a b stx=?)]))
(define-syntax check-values-stx=?
(lambda (stx)
(syntax-case stx []
[(_ actual-expr expected-expr)
(syntax/loc stx
(check/values check-stx=? actual-expr expected-expr))])))
;; ---------------------------------------------------------
;; Predicates
(check-pred stx-xexpr? "A leaf on a string")
(check-pred stx-xexpr? #'"A leaf in syntax")
(check-pred stx-xexpr? #'(div))
(check-pred stx-xexpr? #'(div ((id "top")) "Hello" (p "World")))
(check-pred stx-xexpr? `(div ((id ,#'"top")) "Hello" ,#'(p "World")))
(check-false (stx-txexpr? "A leaf without a tag"))
(check-pred stx-txexpr? '(div))
(check-pred stx-txexpr? #'(div))
(check-pred stx-txexpr? #'(div ((id "top")) "Hello" (p "World")))
(check-pred stx-txexpr? `(div ((id ,#'"top")) "Hello" ,#'(p "World")))
(check-pred stx-txexpr-tag? 'div)
(check-pred stx-txexpr-tag? #'div)
(check-pred stx-txexpr-tag? 'this-is-something-else)
(check-pred stx-txexpr-tag? #'this-is-something-else)
(check-pred stx-txexpr-attrs? '())
(check-pred stx-txexpr-attrs? #'())
(check-pred stx-txexpr-attrs? '((id "top") (style "color: blue")))
(check-pred stx-txexpr-attrs? #'((id "top") (style "color: blue")))
(check-pred stx-txexpr-attrs? `((id "top") (style ,#'"color: blue")))
;; ---------------------------------------------------------
;; Accessors
(check-values-stx=? (stx-txexpr->values '(p))
(values 'p null null))
(check-values-stx=? (stx-txexpr->values '(p "foo"))
(values 'p null '("foo")))
(check-values-stx=? (stx-txexpr->values '(p ((key "value"))))
(values 'p '((key "value")) null))
(check-values-stx=? (stx-txexpr->values '(p ((key "value")) "foo"))
(values 'p '((key "value")) '("foo")))
(check-values-stx=? (stx-txexpr->values #'(p))
(values #'p null null))
(check-values-stx=? (stx-txexpr->values #'(p "foo"))
(values #'p null (list #'"foo")))
(check-values-stx=? (stx-txexpr->values #'(p ((key "value"))))
(values #'p #'((key "value")) null))
(check-values-stx=? (stx-txexpr->values #'(p ((key "value")) "foo"))
(values #'p #'((key "value")) (list #'"foo")))
(check-values-stx=? (stx-txexpr->values `(,#'p))
(values #'p null null))
(check-values-stx=? (stx-txexpr->values `(p ,#'"foo"))
(values 'p null (list #'"foo")))
(check-values-stx=? (stx-txexpr->values `(p ((,#'key "value")) . ,#'("foo")))
(values 'p `((,#'key "value")) (list #'"foo")))
(check-stx=? (stx-txexpr-tag '(p ((key "value"))"foo" (em "square")))
'p)
(check-stx=? (stx-txexpr-tag #'(p ((key "value"))"foo" (em "square")))
#'p)
(check-stx=? (stx-txexpr-attrs '(p ((key "value"))"foo" "bar" (em "square")))
'((key "value")))
(check-stx=? (stx-txexpr-attrs #'(p ((key "value"))"foo" "bar" (em "square")))
#'((key "value")))
(check-stx=? (stx-txexpr-attrs '(p "foo" "bar" (em "square")))
'())
(check-stx=? (stx-txexpr-attrs #'(p "foo" "bar" (em "square")))
'())
(check-stx=? (stx-txexpr-elements '(p "foo" "bar" (em "square")))
'("foo" "bar" (em "square")))
(check-stx=? (stx-txexpr-elements #'(p "foo" "bar" (em "square")))
(list #'"foo" #'"bar" #'(em "square")))
(check-stx=? (stx-txexpr-elements '(p ((k "v"))"foo" "bar" (em "square")))
'("foo" "bar" (em "square")))
(check-stx=? (stx-txexpr-elements #'(p ((k "v"))"foo" "bar" (em "square")))
(list #'"foo" #'"bar" #'(em "square")))
(check-stx=? (stx-txexpr-elements #'(p ((k "v"))"foo" . ("bar" (em "square"))))
(list #'"foo" #'"bar" #'(em "square")))
(check-stx=? (stx-txexpr-elements `(p ((k "v"))"foo" .,#'("bar" (em "square"))))
(list "foo" #'"bar" #'(em "square")))
;; ---------------------------------------------------------

@ -0,0 +1,326 @@
#lang racket/base
(require (for-syntax racket/base racket/syntax syntax/strip-context))
;; use a separate test file to avoid cycle in loading
(define-syntax (test-safe-and-unsafe stx)
(syntax-case stx ()
[(_ . exprs)
(with-syntax ([module-without-contracts (generate-temporary)]
[module-with-contracts (generate-temporary)])
(replace-context stx
#'(begin
(module module-without-contracts racket
(require rackunit "../main.rkt" "check-values.rkt")
. exprs)
(require 'module-without-contracts)
(module module-with-contracts racket
(require rackunit (submod "../main.rkt" safe) "check-values.rkt")
. exprs)
(require 'module-with-contracts))))]))
(test-safe-and-unsafe
(check-true (txexpr-tag? 'foo))
(check-false (txexpr-tag? "foo"))
(check-false (txexpr-tag? 3))
(check-false (txexpr-tags? 'foo))
(check-true (txexpr-tags? '(foo bar)))
(check-true (txexpr-attr? '(key "value")))
(check-false (txexpr-attr? '(key "value" "another")))
(check-false (txexpr-attr? '(key 0 "value")))
(check-true (txexpr-attrs? '()))
(check-true (txexpr-attrs? '((key "value"))))
(check-true (txexpr-attrs? '((key "value") (foo "bar"))))
(check-false (txexpr-attrs? '((key "value") "foo" "bar"))) ; content, not attr
(check-false (txexpr-attrs? '(key "value"))) ; not a nested list
(check-false (txexpr-attrs? '(("key" "value")))) ; two strings
(check-false (txexpr-attrs? '((key value)))) ; two symbols
(check-true (txexpr-element? "string"))
(check-true (txexpr-element? 'amp))
(check-true (txexpr-element? '(p "string")))
(check-true (txexpr-element? 2)) ; a valid-char, but not in v6.0 xml:xexpr?
(check-true (txexpr-element? 65)) ; a valid-char
(check-false (txexpr-element? 0)) ; not a valid-char
(check-true (txexpr-elements? '("p" "foo" "123")))
(check-true (txexpr-elements? '("p" "foo" 123))) ; includes number
(check-true (txexpr-elements? '(p "foo" "123"))) ; includes symbol
(check-false (txexpr-elements? "foo")) ; not a list
(check-false (txexpr-elements? '(((key "value")) "foo" "bar"))) ; includes attr
(check-false (txexpr-elements? '("foo" "bar" ((key "value"))))) ; malformed
(check-true (txexpr? '(p)))
(check-true (txexpr? '(div 2)))
(check-true (txexpr? '(div (div ((foo "bar")) 2))))
(check-true (txexpr? '(p "foo" "bar")))
(check-true (txexpr? '(p ((key "value")) "foo" "bar")))
(check-true (txexpr? '(p 123))) ; content is a number
(check-false (txexpr? "foo")) ; not a list with symbol
(check-false (txexpr? '(p "foo" "bar" ((key "value"))))) ; malformed
(check-false (txexpr? '("p" "foo" "bar"))) ; no name
(check-not-exn (λ _ (validate-txexpr '(p))))
(check-not-exn (λ _ (validate-txexpr '(p "foo" "bar"))))
(check-not-exn (λ _ (validate-txexpr '(p ((key "value")) "foo" "bar"))))
(check-not-exn (λ _ (validate-txexpr '(p () "foo" "bar"))))
(check-not-exn (λ _ (validate-txexpr '(p 123)))) ; content is a valid-char
(check-exn exn:fail? (λ _ (validate-txexpr "foo"))) ; not a list with symbol
(check-exn exn:fail? (λ _ (validate-txexpr '(p "foo" "bar" ((key "value")))))) ; malformed
(check-exn exn:fail? (λ _ (validate-txexpr '("p" "foo" "bar")))) ; no name
(check-exn exn:fail? (λ _ (validate-txexpr '(root ((id "top")(class 42)))))) ; malformed attrs
(check-exn exn:fail? (λ _ (validate-txexpr `(root ,(void))))) ; invalid element type
(define-syntax (check-validate-exn-msg stx)
(syntax-case stx ()
[(_ tx) (syntax/loc stx (check-validate-exn-msg tx ""))]
[(_ tx msg)
(syntax/loc stx
(check-equal? (with-handlers ([exn:fail:contract? (λ (e) (exn-message e))])
(validate-txexpr tx)) msg))]))
;; Root element not a list
(check-validate-exn-msg
"foo"
"validate-txexpr: contract violation\n expected: tagged X-expression\n given: \"foo\"")
;; No name
(check-validate-exn-msg
'("p" "foo" "bar")
"validate-txexpr: tag must be a symbol\n tag: \"p\"\n in: '(\"p\" \"foo\" \"bar\")")
;; Invalid element
(check-validate-exn-msg
'(p "foo" "bar" ((key "value")))
"validate-txexpr: element not a valid element (= txexpr, string, symbol, XML char, cdata, or comment)\n element: '((key \"value\"))\n in: '(p \"foo\" \"bar\" ((key \"value\")))")
;; Malformed attribute list
(check-validate-exn-msg
'(p ((key "val") "foo" "bar") "hi")
"validate-txexpr: attribute is not a list of the form '(symbol \"string\")\n attribute: \"foo\"\n in: '(p ((key \"val\") \"foo\" \"bar\") \"hi\")")
;; Invalid attribute key
(check-validate-exn-msg
'(root ((id "top") (class 42)))
"validate-txexpr: attribute value is not a string\n attribute value: 42\n in: '(root ((id \"top\") (class 42)))")
;; Invalid attribute value
(check-validate-exn-msg
'(root ((id "top") ("class" 42)))
"validate-txexpr: attribute key is not a symbol\n attribute key: \"class\"\n in: '(root ((id \"top\") (\"class\" 42)))")
;; Invalid element type
(check-validate-exn-msg
`(root ,(void))
"validate-txexpr: element not a valid element (= txexpr, string, symbol, XML char, cdata, or comment)\n element: #<void>\n in: '(root #<void>)")
;; (Deeply nested) No name: error should pinpoint element in 'div txexpr
(check-validate-exn-msg
'(fine-outer [[type "valid"]] (div (br) ("p" "foo" "bar")))
"validate-txexpr: element not a valid element (= txexpr, string, symbol, XML char, cdata, or comment)\n element: '(\"p\" \"foo\" \"bar\")\n in: '(div (br) (\"p\" \"foo\" \"bar\"))")
;; (Deeply nested) Invalid element: error should pinpoint element in 'p txexpr
(check-validate-exn-msg
'(fine-outer [[type "valid"]] (div (br) (p "foo" "bar" ((key "value")))))
"validate-txexpr: element not a valid element (= txexpr, string, symbol, XML char, cdata, or comment)\n element: '((key \"value\"))\n in: '(p \"foo\" \"bar\" ((key \"value\")))")
;; (Deeply nested) Malformed attribute list: error should pinpoint attr in 'p txexpr
(check-validate-exn-msg
'(fine-outer [[type "valid"]] (div (br) (p ((key "val") "foo" "bar") "hi")))
"validate-txexpr: attribute is not a list of the form '(symbol \"string\")\n attribute: \"foo\"\n in: '(p ((key \"val\") \"foo\" \"bar\") \"hi\")")
;; (Deeply nested) Invalid attribute key: error should pinpoint attr key in 'p txexpr
(check-validate-exn-msg
'(fine-outer [[type "valid"]] (div (br) (p ((id "top") (class 42)))))
"validate-txexpr: attribute value is not a string\n attribute value: 42\n in: '(p ((id \"top\") (class 42)))")
;; (Deeply nested) Invalid attribute value: error should pinpoint attr val in 'p txexpr
(check-validate-exn-msg
'(fine-outer [[type "valid"]] (div (br) (p ((id "top") ("class" 42)))))
"validate-txexpr: attribute key is not a symbol\n attribute key: \"class\"\n in: '(p ((id \"top\") (\"class\" 42)))")
;; (Deeply nested) Invalid element type: error should pinpoint element in 'p txexpr
(check-validate-exn-msg
`(fine-outer [[type "valid"]] (div (br) (p ,(void))))
"validate-txexpr: element not a valid element (= txexpr, string, symbol, XML char, cdata, or comment)\n element: #<void>\n in: '(p #<void>)")
(check-txexprs-equal? (make-txexpr 'p) '(p))
(check-txexprs-equal? (make-txexpr 'p '((key "value"))) '(p ((key "value"))))
(check-txexprs-equal? (make-txexpr 'p null '("foo" "bar")) '(p "foo" "bar"))
(check-txexprs-equal? (make-txexpr 'p '((key "value")) (list "foo" "bar"))
'(p ((key "value")) "foo" "bar"))
(check-txexprs-equal? (txexpr 'p) '(p))
(check-txexprs-equal? (txexpr 'p '((key "value"))) '(p ((key "value"))))
(check-txexprs-equal? (txexpr 'p null '("foo" "bar")) '(p "foo" "bar"))
(check-txexprs-equal? (txexpr 'p '((key "value")) (list "foo" "bar"))
'(p ((key "value")) "foo" "bar"))
(check-txexprs-equal? (txexpr* 'p) '(p))
(check-txexprs-equal? (txexpr* 'p '((key "value"))) '(p ((key "value"))))
(check-txexprs-equal? (txexpr* 'p null "foo" "bar") '(p "foo" "bar"))
(check-txexprs-equal? (txexpr* 'p '((key "value")) "foo" "bar")
'(p ((key "value")) "foo" "bar"))
(check-values=? (txexpr->values '(p))
(values 'p null null))
(check-values=? (txexpr->values '(p "foo"))
(values 'p null '("foo")))
(check-values=? (txexpr->values '(p ((key "value"))))
(values 'p '((key "value")) null))
(check-values=? (txexpr->values '(p ((key "value")) "foo"))
(values 'p '((key "value")) '("foo")))
(check-equal? (values->list (txexpr->values '(p)))
(txexpr->list '(p)))
(check-equal? (values->list (txexpr->values '(p "foo")))
(txexpr->list '(p "foo")))
(check-equal? (values->list (txexpr->values '(p ((key "value")))))
(txexpr->list '(p ((key "value")))))
(check-equal? (values->list (txexpr->values '(p ((key "value")) "foo")))
(txexpr->list '(p ((key "value")) "foo")))
;; testing the match expander success
(check-match '(p ((key "value")) "leaf")
(txexpr 'p `((key ,val)) (list "leaf"))
(string=? val "value"))
;; testing the match expander failure
(check-false (match '(p ((key "value")) "something")
[(txexpr 'p _ (list "else")) #true]
[_ #false]))
(check-false (match "foo"
[(txexpr _ _ _) #true]
[_ #false]))
(check-equal? (get-tag '(p ((key "value"))"foo" "bar" (em "square"))) 'p)
(check-equal? (get-attrs '(p ((key "value"))"foo" "bar" (em "square"))) '((key "value")))
(check-equal? (get-elements '(p ((key "value"))"foo" "bar" (em "square")))
'("foo" "bar" (em "square")))
(check-equal? (->txexpr-attr-key "foo") 'foo)
(check-equal? (->txexpr-attr-key 'foo) 'foo)
(check-equal? (->txexpr-attr-key (string->path "foo")) 'foo)
(check-equal? (->txexpr-attr-value "foo") "foo")
(check-equal? (->txexpr-attr-value 'foo) "foo")
(check-equal? (->txexpr-attr-value (string->path "foo")) "foo")
(check-equal? (attrs->hash '((foo "bar"))) '#hasheq((foo . "bar")))
(check-equal? (attrs->hash '((foo "bar") (foo "fraw"))) '#hasheq((foo . "bar")))
(check-equal? (attrs->hash #:hash-style? #t '((foo "bar") (foo "fraw"))) '#hasheq((foo . "fraw")))
(check-equal? (attrs->hash '((foo "bar")) '(foo "fraw")) '#hasheq((foo . "bar")))
(check-equal? (attrs->hash '((foo "bar")) '(foo "fraw") 'foo "dog") '#hasheq((foo . "bar")))
(check-exn exn:fail:contract? (λ _ (attrs->hash 'foo "bar" 'zam)))
(check-equal? (sort (hash->attrs '#hash((foo . "bar")(hee . "haw"))) string<? #:key cadr)
(sort '((foo "bar")(hee "haw")) string<? #:key second))
(check-equal? (attr-ref '(p ((foo "bar"))) 'foo) "bar")
(check-exn exn:fail? (λ _ (attr-ref '(p ((foo "bar"))) 'zam)))
(check-equal? (attr-ref '(p ((foo "bar"))) 'zam 42) 42)
(check-equal? (attr-ref '(p ((foo "bar"))) 'zam (λ _ (* 6 7))) 42)
(check-equal? (attr-ref '((foo "bar")) 'foo) "bar")
(check-exn exn:fail? (λ _ (attr-ref '((foo "bar")) 'zam)))
(check-equal? (attr-ref '((foo "bar")) 'zam 42) 42)
(check-equal? (attr-ref '((foo "bar")) 'zam (λ _ (* 6 7))) 42)
(check-txexprs-equal? (attr-set '(p ((foo "bar"))) 'foo "fraw") '(p ((foo "fraw"))))
(check-txexprs-equal? (attr-set* '(p ((foo "bar"))) 'foo "fraw") '(p ((foo "fraw"))))
(check-true (let ([result (attr-set* '(p ((foo "bar"))) 'foo "fraw" 'zim 'zam)])
(and (member '(foo "fraw") (get-attrs result))
(member '(zim "zam") (get-attrs result)) #t)))
(check-txexprs-equal? (attr-join '(p ((foo "bar"))) 'foo "zam") '(p ((foo "bar zam"))))
(check-txexprs-equal? (attr-join '(tx ((foo "bar")) baz (p bin)) 'key 'val)
'(tx ((foo "bar") (key "val")) baz (p bin)))
(check-true (let ([result (attr-join '(p ((foo "bar"))) 'zim "zam")])
(and (member '(foo "bar") (get-attrs result))
(member '(zim "zam") (get-attrs result)) #t)))
(check-true (attrs-have-key? '(p ((color "red")(shape "circle"))) 'color))
(check-true (attrs-have-key? '(p ((color "red")(shape "circle"))) "color"))
(check-false (attrs-have-key? '((color "red")(shape "circle")) 'nonexistent))
(check-true (attrs-equal? '(p ((color "red")(shape "circle")))
'(foo ((color "red")(shape "circle")))))
(check-false (attrs-equal? '(p ((color "red")(shape "circle")))
'(foo ((color "blue")(shape "circle")))))
(check-true (attrs-equal? '(p ((color "red")(shape "circle")))
'(foo ((shape "circle")(color "red")))))
(check-false (attrs-equal? '(p ((color "red")(shape "circle")))
'(foo ((color "red")))))
(check-true (attrs-equal? '((color "red")(shape "circle"))
'((color "red")(shape "circle"))))
(check-false (attrs-equal? '((color "red")(shape "circle"))
'((color "blue")(shape "circle"))))
(check-true (attrs-equal? '((color "red")(shape "circle"))
'((shape "circle")(color "red"))))
(check-false (attrs-equal? '((color "red")(shape "circle"))
'((color "red"))))
(check-true (attrs-equal? '((foo "bar")(foo "zam")(zing "zong"))
'((foo "zam")(zing "zong")(foo "bar"))))
(check-false (attrs-equal? '((foo "bar")(foo "zam")(zing "zong"))
'((foo "different")(zing "zong")(foo "bar"))))
(define-simple-check (check-attrs-equal? attrs1 attrs2) (attrs-equal? attrs1 attrs2))
(check-attrs-equal? '((foo "bar")(foo "zam")) '((foo "zam")(foo "bar")))
(check-txexprs-equal? (remove-attrs '(p ((foo "bar")) "hi")) '(p "hi"))
(check-txexprs-equal? (remove-attrs '(p ((foo "bar")) "hi" (p ((foo "bar")) "hi"))) '(p "hi" (p "hi")))
(check-txexprs-equal? (map-elements (λ (x) (if (string? x) "boing" x))
'(p ((id "zam")) "foo" "bar" (em "square")))
'(p ((id "zam")) "boing" "boing" (em "boing")))
(check-equal? (attr-set '(p) 'foo "zim") '(p ((foo "zim"))))
(check-equal? (attr-set '(p ((foo "bar")(foo "zam"))) 'foo "zim") '(p ((foo "zim"))))
(check-exn exn:fail:contract? (λ _ (attr-set* '(p) 'foo "bar" 'zam)))
(define split-this-tx '(root (meta "foo" "bar") "hello" "world" (meta "foo2" "bar2")
(em "goodnight" "moon" (meta "foo3" "bar3"))))
(define split-predicate (λ (x) (and (txexpr? x) (eq? 'meta (get-tag x)))))
(check-txexprs-equal? (call-with-values (λ () (splitf-txexpr split-this-tx split-predicate)) list)
(list '(root "hello" "world" (em "goodnight" "moon")) '((meta "foo" "bar") (meta "foo2" "bar2") (meta "foo3" "bar3"))))
(define split-proc (λ (x) '(div "foo")))
(check-txexprs-equal? (call-with-values (λ () (splitf-txexpr split-this-tx split-predicate split-proc)) list)
(list '(root (div "foo") "hello" "world" (div "foo") (em "goodnight" "moon" (div "foo"))) '((meta "foo" "bar") (meta "foo2" "bar2") (meta "foo3" "bar3"))))
(define false-pred (λ (x) (and (txexpr? x) (eq? 'nonexistent-tag (get-tag x)))))
(check-equal? (findf*-txexpr split-this-tx split-predicate) '((meta "foo" "bar") (meta "foo2" "bar2") (meta "foo3" "bar3")))
(check-false (findf*-txexpr split-this-tx false-pred))
(check-equal? (findf-txexpr split-this-tx split-predicate) '(meta "foo" "bar"))
(check-false (findf-txexpr split-this-tx false-pred))
(check-equal? (xexpr->html '(root (script "3 > 2") "Why is 3 > 2?"))
"<root><script>3 > 2</script>Why is 3 &gt; 2?</root>")
(check-equal? (xexpr->html '(root (div "<![CDATA[3 > 2]]>") "Why is 3 > 2?"))
"<root><div><![CDATA[3 > 2]]></div>Why is 3 &gt; 2?</root>")
;; comment
(check-equal? (xexpr->html '(root "<!-- comment -->" "Why is 3 > 2?"))
"<root><!-- comment -->Why is 3 &gt; 2?</root>")
;; malformed comment: merged with next string
(check-equal? (xexpr->html '(root "<!-- comment -->Why is 3 > 2?"))
"<root>&lt;!-- comment --&gt;Why is 3 &gt; 2?</root>")
;; malformed comment: missing double hyphen at end
(check-equal? (xexpr->html '(root "<!-- comment ->" "Why is 3 > 2?"))
"<root>&lt;!-- comment -&gt;Why is 3 &gt; 2?</root>"))

@ -0,0 +1,39 @@
#lang racket/base
(require "../main.rkt" sugar/define)
(module+ test
(require rackunit "../main.rkt"))
(define+provide+safe (attr-ref* tx key)
(txexpr? can-be-txexpr-attr-key? . -> . txexpr-attr-values?)
(define results empty)
(let loop ([tx tx])
(when (and (txexpr? tx) (attrs-have-key? tx key) (attr-ref tx key))
(set! results (cons (attr-ref tx key) results))
(map loop (get-elements tx))
(void)))
(reverse results))
(module+ test
(check-txexprs-equal? (attr-ref* '(root ((foo "bar")) "hello" "world" (meta ((foo "zam")) "bar2")
(em ((foo "zam")) "goodnight" "moon")) 'foo) '("bar" "zam" "zam"))
(check-txexprs-equal? (attr-ref* '(root ((foo "bar")) "hello" "world" (meta ((foo "zam")) "bar2")
(em ((foo "zam")) "goodnight" "moon")) 'nonexistent-key) '()))
;; convert list of alternating keys & values to attr
;; with override behavior (using hash)
(define+provide+safe (merge-attrs . items)
(() #:rest list-of-can-be-txexpr-attrs? . ->* . txexpr-attrs?)
(hash->attrs (apply (λ xs (attrs->hash #:hash-style? #t xs)) items)))
(module+ test
(check-true (attrs-equal? (merge-attrs 'foo "bar") '((foo "bar"))))
(check-true (attrs-equal? (merge-attrs '(foo "bar")) '((foo "bar"))))
(check-true (attrs-equal? (merge-attrs '((foo "bar"))) '((foo "bar"))))
(check-true (attrs-equal? (merge-attrs "foo" 'bar) '((foo "bar"))))
(check-true (attrs-equal? (merge-attrs "foo" "bar" "goo" "gar") '((foo "bar")(goo "gar"))))
(check-true (attrs-equal? (merge-attrs (merge-attrs "foo" "bar" "goo" "gar") "hee" "haw")
'((foo "bar")(goo "gar")(hee "haw"))))
(check-true (attrs-equal? (merge-attrs '((foo "bar")(goo "gar")) "foo" "haw") '((foo "haw")(goo "gar")))))
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