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typesetting/quad/quad/qexpr.rkt

108 lines
3.6 KiB
Racket

#lang debug racket/base
(require xml
racket/dict
racket/string
racket/match
racket/list
txexpr
"quad.rkt")
(provide (all-defined-out))
(module+ test (require rackunit))
;; should we allow quads within a qexpr? I say yes
(define permissive-qexprs (make-parameter #t))
(define (valid-tag? tag) (and (memq tag '(q quad)) #t))
(define (qexpr? x)
;; a qexpr is like an xexpr, but more lenient in some ways (possibly allows quads)
;; and less in others (only allows 'q or 'quad as tag names, only allows strings or qexprs as elements)
;; attrs are open-ended
(match x
[(cons (? valid-tag?) rest)
(match rest
[(list (? txexpr-attrs?) (? qexpr?) ...) #t]
[(list (? qexpr?) ...) #t]
[_ #f])]
[(? string?) #t]
[(? quad?) (permissive-qexprs)]
[_ #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-false (qexpr? '(q #\H)))
(check-false (qexpr? '(quad #\H)))
(check-false (qexpr? '(span #\H)))
(check-true (qexpr? '(quad "Hello world")))
(check-true (qexpr? `(quad "Hello " ,(q "world")))))
(define (quad-name q) (string->symbol (string-trim (symbol->string (object-name q)) "$")))
(define (qexpr #:clean-attrs? [clean-attrs? #f]
#:name [name 'q]
attrs . elems)
(define new-attrs (if clean-attrs? (remove-duplicates attrs #:key car) attrs))
(define new-elems (match elems
[(list (? char? c)) (list (string c))]
[(list (? list? xs)) xs]
[else elems]))
(cond
[(empty? new-attrs) (list* name new-elems)]
[else (list* name new-attrs new-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 (quad->qexpr q)
(let loop ([x q])
(cond
[(quad? x) (apply qexpr #:name (quad-name x) #:clean-attrs? #t (hash->qattrs (quad-attrs x)) (map loop (quad-elems x)))]
[else x])))
(define (qexpr->quad x)
(unless (qexpr? x)
(raise-argument-error 'qexpr->quad "qexpr" x))
(let loop ([x x])
(match x
[(cons (? valid-tag?) rest)
(match rest
[(list (? txexpr-attrs? attrs) (? qexpr? elems) ...)
(define mheq (make-hash)) ; want mutable hash
(for ([kv (in-list attrs)])
(match-define (list k v) kv)
;; coerce number strings to actual numbers
(hash-set! mheq k (or (string->number v) v)))
(q #:attrs mheq #:elems (map loop elems))]
[(list (? qexpr? elems) ...)
(q #:elems (map loop elems))])]
[_ x])))
(module+ test
(check-equal?
(qexpr->quad `(q ((font "Charter") (fontsize "12")) (q "Foo bar") ,(make-quad "zzz") (q "Zim Zam")))
(q (hasheq 'font "Charter" 'fontsize 12) (q "Foo bar") (q "zzz") (q "Zim Zam"))))
(define (qml->qexpr x)
(parameterize ([permissive-xexprs #t]
[xexpr-drop-empty-attributes #t])
(string->xexpr x)))
(define (qexpr->qml x)
(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")))