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pollen/main.rkt

113 lines
5.1 KiB
Racket

#lang racket/base
(require racket/list)
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(require (planet mb/pollen/tools) (planet mb/pollen/main-helper))
(require (only-in (planet mb/pollen/pmap) pmap-decode))
(require (only-in (planet mb/pollen/predicates) pmap?))
(require (only-in (planet mb/pollen/pollen-file-tools) has-ext?))
(require (only-in (planet mb/pollen/world) POLLEN_MAP_EXT))
(provide (except-out (all-from-out racket/base) #%module-begin)
(rename-out [module-begin #%module-begin]))
(define-syntax-rule (module-begin expr ...)
(#%module-begin
;; this is here only so that dynamic-rerequire of a pollen module
;; transitively reloads the extras also.
;; if this isn't here, then dynamic-rerequire can't see them
;; and thus they are not tracked for changes.
(require-extras)
;; We want our module language to support require & provide
;; which are only supported at the module level, so ...
;; create a submodule to contain the input
;; and export as needed
;; doclang2_raw is a clone of scribble/doclang2 with decode disabled
;; helpful because it collects & exports content via 'doc
(module pollen-inner (planet mb/pollen/lang/doclang2_raw)
;; use same requires as top of main.rkt
;; (can't import them from surrounding module due to submodule rules)
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(require (planet mb/pollen/tools) (planet mb/pollen/main-helper))
(require (only-in (planet mb/pollen/pmap) pmap-subtopic))
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(require-extras #:provide #t) ; brings in the project require files
;; #%top binding catches ids that aren't defined
;; here, convert them to basic xexpr
;; #%top is a syntax transformer that returns a function
;; λ x captures all the args (vs. λ(x), which only catches one)
;; and id is not spliced because it's syntax, not a true variable
;; WARNING! This is convenient for writing pollen documents
;; (which is why it works this way)
;; but it makes debugging tricky, because an undefined (symbol item ...)
;; is just treated as a valid tagged-xexpr, not an undefined function.
(define-syntax-rule (#%top . id)
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(λ x `(id ,@x)))
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expr ... ; body of module
;; set up a hook for identifier 'here'
;; (but under a different name to avoid macrofication)
(define inner-here here)
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(provide (all-defined-out)))
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(require 'pollen-inner) ; provides doc & #%top, among other things
;; prepare the elements, and append inner-here as meta.
(define all-elements (append
;; append inner-here as meta
;; put it first so it can be overridden by custom meta later on
(list `(meta "here" ,inner-here))
(cond
;; doc is probably a list, but might be a single string
[(string? doc) (list doc)]
[(tagged-xexpr? doc) (list doc)] ; if it's a single nx, just leave it
[(list? doc) doc]))) ; if it's nx content, splice it in
;; split out the metas now (in raw form)
(define-values (metas-raw main-raw)
(split-tag-from-xexpr 'meta (make-tagged-xexpr 'irrelevant-tag empty all-elements)))
(define metas (make-meta-hash metas-raw))
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;; Policy: here in the core lang, do as little to main as possible.
;; The point is just to set it up for further processing.
;; Unlike Scribble, which insists on decoding,
;; Pollen just passes through the minimally processed data.
;; one exception: if file extension marks it as pmap, send it to the pmap decoder instead.
(define source-is-pmap?
;; this tests inner-here (which is always the file name)
;; rather than (get metas 'here) which might have been overridden.
;; Because if it's overridden to something other than *.pmap,
;; pmap processing will fail.
;; This defeats rule that pmap file suffix triggers pmap decoding.
((->path inner-here) . has-ext? . POLLEN_MAP_EXT))
(define main (apply (if source-is-pmap?
pmap-decode
;; most files will go this way.
;; Root is treated as a function.
;; If it's not defined elsewhere,
;; it just hits #%top and becomes a tagged-xexpr.
root) (tagged-xexpr-elements main-raw)))
(provide main metas
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(except-out (all-from-out 'pollen-inner) inner-here) ; everything from user
(rename-out (inner-here here))) ; change identifier back (now safe from macrofication)
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(module+ main
(displayln ";-------------------------")
(displayln (string-append "; pollen decoded 'main" (if source-is-pmap? " (as pmap)" "")))
(displayln ";-------------------------")
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main
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(displayln "")
(if source-is-pmap?
(displayln (format "(pmap? main) ~a" (pmap? main)))
(displayln (format "(tagged-xexpr? main) ~a" (tagged-xexpr? main))))
(displayln "")
(displayln ";-------------------------")
(displayln "; pollen 'metas")
(displayln ";-------------------------")
metas
)))