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93 lines
3.3 KiB
Racket
93 lines
3.3 KiB
Racket
#lang racket/base
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(require racket/contract/base
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syntax/stx)
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(require racket/list)
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(define (syntax->string c)
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(let* ([s (open-output-string)]
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[l (syntax->list c)]
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[init-col (or (syntax-column (first l)) 0)]
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[col init-col]
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[line (or (syntax-line (first l)) 0)])
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(define (advance c init-line!)
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(let ([c (syntax-column c)]
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[l (syntax-line c)])
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(when (and l (l . > . line))
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(for-each (λ (_) (newline)) (range (- l line)))
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(set! line l)
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(init-line!))
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(when c
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(display (make-string (max 0 (- c col)) #\space))
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(set! col c))))
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(parameterize ([current-output-port s]
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[read-case-sensitive #t])
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(define (loop init-line!)
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(lambda (c)
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(cond
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[(eq? 'code:blank (syntax-e c))
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(advance c init-line!)]
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[(eq? '_ (syntax-e c)) (void)]
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[(eq? '... (syntax-e c))
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(void)]
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[(and (pair? (syntax-e c))
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(eq? (syntax-e (car (syntax-e c))) 'code:comment))
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(advance c init-line!)
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(printf "; ")
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(display (syntax-e (cadr (syntax->list c))))]
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[(and (pair? (syntax-e c))
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(eq? (syntax-e (car (syntax-e c))) 'code:contract))
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(advance c init-line!)
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(printf "; ")
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(let* ([l (cdr (syntax->list c))]
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[s-col (or (syntax-column (first l)) col)])
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(set! col s-col)
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(for-each (loop (lambda ()
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(set! col s-col)
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(printf "; ")))
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l))]
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[(and (pair? (syntax-e c))
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(eq? (syntax-e (car (syntax-e c))) 'quote))
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(advance c init-line!)
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(printf "'")
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(let ([i (cadr (syntax->list c))])
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(set! col (or (syntax-column i) col))
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((loop init-line!) i))]
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[(pair? (syntax-e c))
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(advance c init-line!)
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(define c-paren-shape (syntax-property c 'paren-shape))
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(printf (format "~a" (or c-paren-shape #\()))
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(set! col (+ col 1))
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(map (loop init-line!) (syntax->list c))
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(printf (case c-paren-shape
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[(#\[) "]"]
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[(#\{) "}"]
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[else ")"]))
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(set! col (+ col 1))]
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[(vector? (syntax-e c))
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(advance c init-line!)
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(printf "#(")
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(set! col (+ col 2))
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(map (loop init-line!) (vector->list (syntax-e c)))
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(printf ")")
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(set! col (+ col 1))]
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[else
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(advance c init-line!)
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(let ([s (format "~s" (syntax-e c))])
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(set! col (+ col (string-length s)))
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(display s))])))
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(for-each (loop (lambda () (set! col init-col))) l))
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(get-output-string s)))
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(provide/contract [syntax->string (-> (and/c syntax? stx-list?)
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string?)])
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(module+ test
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(require rackunit)
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(check-equal? (syntax->string
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#'((define (f x)
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[+ x x])
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(define (g x)
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(* x x)))) "(define (f x)\n [+ x x])\n\n(define (g x)\n (* x x))"))
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