From 593a832dbb328b21ecca3a2cb35b8ddee8210306 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Wed, 2 Jan 2019 16:55:29 -0800
Subject: [PATCH] improve

---
 quad/qtest/typewriter.rkt |  5 ++-
 quad/quad/main.rkt        |  2 +
 quad/quad/qexpr.rkt       | 84 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+), 1 deletion(-)
 create mode 100644 quad/quad/qexpr.rkt

diff --git a/quad/qtest/typewriter.rkt b/quad/qtest/typewriter.rkt
index 4b17e1dd..9af984d2 100644
--- a/quad/qtest/typewriter.rkt
+++ b/quad/qtest/typewriter.rkt
@@ -172,9 +172,12 @@
        #'(#%module-begin
           (define qs (list . QS))
           (define lotsa-qs (append* (make-list (string->number (string-trim REP)) qs)))
-          (run (apply quad (hasheq 'fontsize "12") lotsa-qs) PS)
+          (run (qexpr->quad (apply quad #:fontsize "12" lotsa-qs)) PS)
           (void)))]))
 
+(define quad (default-tag-function 'quad))
+(provide quad)
+
 (module reader syntax/module-reader
   qtest/typewriter
   #:read quad-read
diff --git a/quad/quad/main.rkt b/quad/quad/main.rkt
index 8f9e3cb4..eb1cc047 100644
--- a/quad/quad/main.rkt
+++ b/quad/quad/main.rkt
@@ -2,12 +2,14 @@
 
 (require "atomize.rkt"
 "quad.rkt"
+"qexpr.rkt"
 "break.rkt"
 "position.rkt"
 "param.rkt")
 
 (provide (all-from-out "atomize.rkt"
 "quad.rkt"
+"qexpr.rkt"
 "break.rkt"
 "position.rkt"
 "param.rkt"))
\ No newline at end of file
diff --git a/quad/quad/qexpr.rkt b/quad/quad/qexpr.rkt
new file mode 100644
index 00000000..a044e622
--- /dev/null
+++ b/quad/quad/qexpr.rkt
@@ -0,0 +1,84 @@
+#lang debug racket/base
+(require xml
+         racket/contract
+         racket/class
+         racket/dict
+         racket/string
+         racket/match
+         racket/list
+         txexpr 
+         "quad.rkt" sugar/debug)
+(provide (all-defined-out))
+
+(module+ test (require rackunit))
+
+(define/contract (qexpr? x)
+  ;; a qexpr is like an xexpr, but more lenient in some ways (allows single char as body element)
+  ;; and less in others (only allows 'q or 'quad as tag names)
+  (any/c . -> . boolean?)
+  (define (valid-tag? tag) (and (memq tag '(q quad)) #t))
+  (match x
+    [(? txexpr?) #t]
+    [(list (? symbol? tag) (? char? c)) #t]
+    [(? string?) #t]
+    [else #f]))
+
+
+(module+ test
+  (check-true (qexpr? "Hello world"))
+  (check-true (qexpr? '(q "Hello world")))
+  (check-true (qexpr? '(quad "Hello world")))
+  #;(check-false (qexpr? '(div "Hello world")))
+  (check-true (qexpr? '(q #\H)))
+  (check-true (qexpr? '(quad #\H)))
+  #;(check-false (qexpr? '(span #\H)))
+  (check-true (qexpr? '(quad "Hello world")))
+  (check-false (qexpr? 'q)))
+
+(define (quad-name q) (string->symbol (string-trim (symbol->string (object-name q)) "$")))
+
+(define/contract (qexpr #:clean-attrs? [clean-attrs? #f]
+                        #:name [name 'q]
+                        attrs . elems)
+  ((txexpr-attrs?) (#:clean-attrs? any/c #:name txexpr-tag?) #:rest (or/c txexpr-elements? (list/c char?)) . ->* . qexpr?)
+  (txexpr name (if clean-attrs? (remove-duplicates attrs #:key car) attrs) (match elems
+                                                                             [(list (? char? c)) (list (string c))]
+                                                                             [else elems])))
+
+(module+ test
+  (check-equal? (qexpr null "foo") '(q "foo"))
+  (check-equal? (qexpr '((k "v")) "foo") '(q ((k "v")) "foo"))
+  (check-equal? (qexpr '((k "v2")(k "v1")) "foo") '(q ((k "v2")(k "v1")) "foo"))
+  (check-equal? (qexpr #:clean-attrs? #t '((k "v2")(k "v1")) "foo") '(q ((k "v2")) "foo")))
+
+(define (hash->qattrs attr-hash)
+  (for/list ([(k v) (in-dict (hash->list attr-hash))])
+    (list k (format "~a" v))))
+
+(define/contract (quad->qexpr q)
+  (quad? . -> . qexpr?)
+  (let loop ([x q])
+    (cond
+      [(quad? x) (apply qexpr #:name (quad-name x) #:clean-attrs? #t (hash->qattrs (send x attrs)) (map loop (send x elems)))]
+      [else x])))
+
+(define/contract (qexpr->quad x)
+  (qexpr? . -> . quad?)
+  (if (txexpr? x)
+      (make-object quad% (attrs->hash (get-attrs x)) (map qexpr->quad (get-elements x)))
+      x))
+
+(define/contract (qml->qexpr x)
+  (string? . -> . qexpr?)
+  (parameterize ([permissive-xexprs #t]
+                 [xexpr-drop-empty-attributes #t])
+    (string->xexpr x)))
+
+(define/contract (qexpr->qml x)
+  (qexpr? . -> . string?)
+  (xexpr->string x))
+
+(module+ test
+  (check-equal? (qml->qexpr (qexpr->qml '(q "hi"))) '(q "hi"))
+  (check-equal? (qml->qexpr (qexpr->qml '(q () "hi"))) '(q "hi"))
+  (check-equal? (qml->qexpr (qexpr->qml '(q ((foo "bar")) "hi"))) '(q ((foo "bar")) "hi")))
\ No newline at end of file