[WIP] syntax-rules: rewrite syntax-rules.scm
[syntax-rules] bugfix s/generate-representation/template-representation/g [WIP] rewrite syntax-rules [syntax-rules] bugfix s/generate-representation/template-representation/g [syntax-rules] bugfix
This commit is contained in:
Yuichi Nishiwaki
parent
d741efe294
commit
43f1f6bb70
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@ -1,348 +1,194 @@
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(define-library (picrin syntax-rules)
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(import (picrin base)
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(picrin control)
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(picrin macro))
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(define-syntax define-auxiliary-syntax
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(er-macro-transformer
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(lambda (expr r c)
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(list (r 'define-syntax) (cadr expr)
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(list (r 'lambda) '_
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(list (r 'lambda) '_
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(list (r 'error) (list (r 'string-append) "invalid use of auxiliary syntax: '" (symbol->string (cadr expr)) "'"))))))))
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(define-syntax (define-auxiliary-syntax var)
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#`(define-macro #,var
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(lambda _
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(error "invalid use of auxiliary syntax" '#,var))))
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(define-auxiliary-syntax _)
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(define-auxiliary-syntax ...)
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(define (walk proc expr)
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(cond
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((null? expr)
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'())
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((pair? expr)
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(cons (walk proc (car expr))
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(walk proc (cdr expr))))
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((vector? expr)
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(list->vector (map proc (vector->list expr))))
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(else
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(proc expr))))
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(define (succ n)
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(+ n 1))
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(define (flatten expr)
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(let ((list '()))
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(walk
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(lambda (x)
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(set! list (cons x list)))
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expr)
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(reverse list)))
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(define (pred n)
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(if (= n 0)
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0
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(- n 1)))
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(define (reverse* l)
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;; (reverse* '(a b c d . e)) => (e d c b a)
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(let loop ((a '())
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(d l))
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(if (pair? d)
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(loop (cons (car d) a) (cdr d))
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(cons d a))))
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(define (every? pred l)
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(if (null? l)
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(define (every? args)
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(if (null? args)
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#t
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(and (pred (car l)) (every? pred (cdr l)))))
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(if (car args)
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(every? (cdr args))
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#f)))
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(define-syntax syntax-rules
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(er-macro-transformer
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(lambda (form r compare)
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(define _define (r 'define))
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(define _let (r 'let))
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(define _if (r 'if))
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(define _begin (r 'begin))
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(define _lambda (r 'lambda))
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(define _set! (r 'set!))
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(define _not (r 'not))
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(define _and (r 'and))
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(define _car (r 'car))
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(define _cdr (r 'cdr))
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(define _cons (r 'cons))
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(define _pair? (r 'pair?))
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(define _null? (r 'null?))
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(define _symbol? (r 'symbol?))
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(define _vector? (r 'vector?))
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(define _eqv? (r 'eqv?))
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(define _string=? (r 'string=?))
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(define _map (r 'map))
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(define _vector->list (r 'vector->list))
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(define _list->vector (r 'list->vector))
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(define _quote (r 'quote))
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(define _quasiquote (r 'quasiquote))
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(define _unquote (r 'unquote))
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(define _unquote-splicing (r 'unquote-splicing))
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(define _syntax-error (r 'syntax-error))
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(define _escape (r 'escape))
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(define _er-macro-transformer (r 'er-macro-transformer))
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(define (filter f list)
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(if (null? list)
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'()
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(if (f (car list))
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(cons (car list)
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(filter f (cdr list)))
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(filter f (cdr list)))))
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(define (var->sym v)
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(let loop ((cnt 0)
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(v v))
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(if (symbol? v)
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(string->symbol
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(string-append (symbol->string v) "/" (number->string cnt)))
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(loop (+ 1 cnt) (car v)))))
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(define (map-keys f assoc)
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(map (lambda (s) `(,(f (car s)) . ,(cdr s))) assoc))
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(define push-var list)
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(define (map-values f assoc)
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(map (lambda (s) `(,(car s) . ,(f (cdr s)))) assoc))
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(define (compile-match ellipsis literals pattern)
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(letrec ((compile-match-base
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(lambda (pattern)
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(cond ((member pattern literals compare)
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(values
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`(,_if (,_and (,_symbol? expr) (cmp expr (rename ',pattern)))
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#f
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(exit #f))
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'()))
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((compare pattern (r '_)) (values #f '()))
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((and ellipsis (compare pattern ellipsis))
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(values `(,_syntax-error "invalid pattern") '()))
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((symbol? pattern)
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(values `(,_set! ,(var->sym pattern) expr) (list pattern)))
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((pair? pattern)
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(compile-match-list pattern))
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((vector? pattern)
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(compile-match-vector pattern))
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((string? pattern)
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(values
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`(,_if (,_not (,_string=? ',pattern expr))
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(exit #f))
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'()))
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(else
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(values
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`(,_if (,_not (,_eqv? ',pattern expr))
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(exit #f))
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'())))))
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;; TODO
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;; - constants
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;; - literals
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;; - custom ellipsis
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;; - splicing
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;; - placeholder
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;; - vector
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(compile-match-list
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(lambda (pattern)
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(let loop ((pattern pattern)
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(matches '())
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(vars '())
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(accessor 'expr))
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(cond ;; (hoge)
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((not (pair? (cdr pattern)))
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(let*-values (((match1 vars1) (compile-match-base (car pattern)))
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((match2 vars2) (compile-match-base (cdr pattern))))
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(values
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`(,_begin ,@(reverse matches)
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(,_if (,_pair? ,accessor)
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(,_begin
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(,_let ((expr (,_car ,accessor)))
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,match1)
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(,_let ((expr (,_cdr ,accessor)))
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,match2))
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(exit #f)))
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(append vars (append vars1 vars2)))))
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;; (hoge ... rest args)
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((and ellipsis (compare (cadr pattern) ellipsis))
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(let-values (((match-r vars-r) (compile-match-list-reverse pattern)))
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(values
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`(,_begin ,@(reverse matches)
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(,_let ((expr (,_let loop ((a ())
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(d ,accessor))
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(,_if (,_pair? d)
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(loop (,_cons (,_car d) a) (,_cdr d))
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(,_cons d a)))))
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,match-r))
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(append vars vars-r))))
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(else
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(let-values (((match1 vars1) (compile-match-base (car pattern))))
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(loop (cdr pattern)
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(cons `(,_if (,_pair? ,accessor)
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(,_let ((expr (,_car ,accessor)))
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,match1)
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(exit #f))
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matches)
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(append vars vars1)
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`(,_cdr ,accessor))))))))
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;; p ::= ()
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;; | var
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;; | (p . p)
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;; | (p ...)
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(compile-match-list-reverse
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(lambda (pattern)
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(let loop ((pattern (reverse* pattern))
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(matches '())
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(vars '())
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(accessor 'expr))
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(cond ((and ellipsis (compare (car pattern) ellipsis))
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(let-values (((match1 vars1) (compile-match-ellipsis (cadr pattern))))
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(values
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`(,_begin ,@(reverse matches)
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(,_let ((expr ,accessor))
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,match1))
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(append vars vars1))))
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(else
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(let-values (((match1 vars1) (compile-match-base (car pattern))))
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(loop (cdr pattern)
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(cons `(,_let ((expr (,_car ,accessor))) ,match1) matches)
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(append vars vars1)
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`(,_cdr ,accessor))))))))
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(define (compile ellipsis literals rules)
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(compile-match-ellipsis
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(lambda (pattern)
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(let-values (((match vars) (compile-match-base pattern)))
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(values
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`(,_let loop ((expr expr))
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(,_if (,_not (,_null? expr))
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(,_let ,(map (lambda (var) `(,(var->sym var) '())) vars)
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(,_let ((expr (,_car expr)))
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,match)
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,@(map
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(lambda (var)
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`(,_set! ,(var->sym (push-var var))
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(,_cons ,(var->sym var) ,(var->sym (push-var var)))))
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vars)
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(loop (,_cdr expr)))))
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(map push-var vars)))))
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(define (many? pat)
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(and (pair? pat)
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(pair? (cdr pat))
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(variable? (cadr pat))
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(variable=? (cadr pat) ellipsis)
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(eq? (cddr pat) '())))
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(compile-match-vector
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(lambda (pattern)
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(let-values (((match vars) (compile-match-base (vector->list pattern))))
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(values
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`(,_if (,_vector? expr)
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(,_let ((expr (,_vector->list expr)))
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,match)
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(exit #f))
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vars)))))
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(let-values (((match vars) (compile-match-base (cdr pattern))))
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(values `(,_let ((expr (,_cdr expr)))
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,match
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(define (pattern-validator pat) ; pattern -> validator
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(letrec
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((pattern-validator
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(lambda (pat form)
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(cond
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((null? pat)
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#`(null? #,form))
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((variable? pat)
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#t)
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vars))))
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;;; compile expand
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(define (compile-expand ellipsis reserved template)
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(letrec ((compile-expand-base
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(lambda (template ellipsis-valid)
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(cond ((member template reserved eq?)
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(values (var->sym template) (list template)))
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((symbol? template)
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(values `(rename ',template) '()))
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((pair? template)
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(compile-expand-list template ellipsis-valid))
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((vector? template)
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(compile-expand-vector template ellipsis-valid))
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((many? pat)
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(let ((validator (pattern-validator (car pat) 'it)))
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#`(and (list? #,form)
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(every? (map (lambda (#,'it) #,validator) #,form)))))
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((pair? pat)
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#`(and (pair? #,form)
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#,(pattern-validator (car pat) #`(car #,form))
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#,(pattern-validator (cdr pat) #`(cdr #,form))))
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(else
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(values `',template '())))))
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#f)))))
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(pattern-validator pat 'it)))
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(compile-expand-list
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(lambda (template ellipsis-valid)
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(let loop ((template template)
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(expands '())
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(vars '()))
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(cond ;; (... hoge)
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((and ellipsis-valid
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(pair? template)
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(compare (car template) ellipsis))
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(if (and (pair? (cdr template)) (null? (cddr template)))
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(compile-expand-base (cadr template) #f)
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(values '(,_syntax-error "invalid template") '())))
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;; hoge
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((not (pair? template))
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(let-values (((expand1 vars1)
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(compile-expand-base template ellipsis-valid)))
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(values
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`(,_quasiquote (,@(reverse expands) . (,_unquote ,expand1)))
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(append vars vars1))))
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;; (a ... rest syms)
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((and ellipsis-valid
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(pair? (cdr template))
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(compare (cadr template) ellipsis))
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(let-values (((expand1 vars1)
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(compile-expand-base (car template) ellipsis-valid)))
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(loop (cddr template)
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(cons
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`(,_unquote-splicing
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(,_map (,_lambda ,(map var->sym vars1) ,expand1)
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,@(map (lambda (v) (var->sym (push-var v))) vars1)))
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expands)
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(append vars (map push-var vars1)))))
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(else
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(let-values (((expand1 vars1)
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(compile-expand-base (car template) ellipsis-valid)))
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(loop (cdr template)
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(cons
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`(,_unquote ,expand1)
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expands)
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(append vars vars1))))))))
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(define (pattern-variables pat) ; pattern -> (freevar)
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(cond
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((null? pat)
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'())
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((variable? pat)
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`(,pat))
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((many? pat)
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(pattern-variables (car pat)))
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((pair? pat)
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(append (pattern-variables (car pat))
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(pattern-variables (cdr pat))))))
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(compile-expand-vector
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(lambda (template ellipsis-valid)
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(let-values (((expand1 vars1)
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(compile-expand-base (vector->list template) ellipsis-valid)))
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(values
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`(,_list->vector ,expand1)
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vars1)))))
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(define (pattern-levels pat) ; pattern -> ((var * int))
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(cond
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((null? pat)
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'())
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((variable? pat)
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`((,pat . 0)))
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((many? pat)
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(map-values succ (pattern-levels (car pat))))
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((pair? pat)
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(append (pattern-levels (car pat))
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(pattern-levels (cdr pat))))))
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(compile-expand-base template ellipsis)))
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(define (pattern-selectors pat) ; pattern -> ((var * selector))
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(letrec
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((pattern-selectors
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(lambda (pat form)
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(cond
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((null? pat)
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'())
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((variable? pat)
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`((,pat . ,form)))
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((many? pat)
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(let ((envs (pattern-selectors (car pat) 'it)))
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(map-values (lambda (s) #`(map (lambda (#,'it) #,s) #,form)) envs)))
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((pair? pat)
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(append (pattern-selectors (car pat) #`(car #,form))
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(pattern-selectors (cdr pat) #`(cdr #,form))))))))
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(pattern-selectors pat 'it)))
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(define (check-vars vars-pattern vars-template)
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;;fixme
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#t)
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(define (template-representation pat levels selectors)
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(cond
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((null? pat)
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'())
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((variable? pat)
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(let ((it (assq pat levels)))
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(if it
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(if (= 0 (cdr it))
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(cdr (assq pat selectors))
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(error "unmatched pattern variable level" pat))
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#`'#,pat)))
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((many? pat)
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(letrec*
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((inner-pat
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(car pat))
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(inner-vars
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(filter (lambda (v) (assq v levels)) (pattern-variables inner-pat)))
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(inner-tmps
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(map (lambda (v) #'it) inner-vars))
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(inner-levels
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(map (lambda (s) `(,(car s) . ,(pred (cdr s)))) levels))
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(inner-selectors
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(map cons inner-vars inner-tmps))
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(inner-rep
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(template-representation inner-pat inner-levels inner-selectors))
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(filtered-selectors
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(map (lambda (v) (assq v selectors)) inner-vars))
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;; ((a . (x1 x2)) (b . (y1 y2 y3)) (c . z1)) -> ((x1 x2) (y1 y2 y3) (z1))
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(list-of-selectors
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(map (lambda (x) (if (list? x) x (list x))) (map cdr filtered-selectors))))
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#`(map (lambda #,inner-tmps #,inner-rep) #,@list-of-selectors)))
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((pair? pat)
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#`(cons #,(template-representation (car pat) levels selectors)
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#,(template-representation (cdr pat) levels selectors)))))
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(define (compile-rule ellipsis literals rule)
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(let ((pattern (car rule))
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(template (cadr rule)))
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(let*-values (((match vars-match)
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(compile-match ellipsis literals pattern))
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((expand vars-expand)
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(compile-expand ellipsis (flatten vars-match) template)))
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(if (check-vars vars-match vars-expand)
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(list vars-match match expand)
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'mismatch))))
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(define (compile-rule pattern template)
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(let ((levels
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(pattern-levels pattern))
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(selectors
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(pattern-selectors pattern)))
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(template-representation template levels selectors)))
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(define (expand-clauses clauses rename)
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(cond ((null? clauses)
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`(,_quote (syntax-error "no matching pattern")))
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((compare (car clauses) 'mismatch)
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`(,_syntax-error "invalid rule"))
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(else
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(let ((vars (list-ref (car clauses) 0))
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(match (list-ref (car clauses) 1))
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(expand (list-ref (car clauses) 2)))
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`(,_let ,(map (lambda (v) (list (var->sym v) '())) vars)
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(,_let ((result (,_escape (,_lambda (exit) ,match))))
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(,_if result
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,expand
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,(expand-clauses (cdr clauses) rename))))))))
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(define (compile-rules rules)
|
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(if (null? rules)
|
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#`(error "unmatch")
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(let ((pattern (car (car rules)))
|
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(template (cadr (car rules))))
|
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#`(if #,(pattern-validator pattern)
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#,(compile-rule pattern template)
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#,(compile-rules (cdr rules))))))
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|
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(define (normalize-form form)
|
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(if (and (list? form) (>= (length form) 2))
|
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(let ((ellipsis '...)
|
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(literals (cadr form))
|
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(rules (cddr form)))
|
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(define (compile rules)
|
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#`(lambda #,'it
|
||||
#,(compile-rules rules)))
|
||||
|
||||
(when (symbol? literals)
|
||||
(set! ellipsis literals)
|
||||
(set! literals (car rules))
|
||||
(set! rules (cdr rules)))
|
||||
(let ((rules (map-keys cdr rules))) ; TODO: check pattern head is a variable
|
||||
(compile rules)))
|
||||
|
||||
(if (and (symbol? ellipsis)
|
||||
(list? literals)
|
||||
(every? symbol? literals)
|
||||
(list? rules)
|
||||
(every? (lambda (l) (and (list? l) (= (length l) 2))) rules))
|
||||
(if (member ellipsis literals compare)
|
||||
`(syntax-rules #f ,literals ,@rules)
|
||||
`(syntax-rules ,ellipsis ,literals ,@rules))
|
||||
#f))
|
||||
#f))
|
||||
(define-syntax (syntax-rules . args)
|
||||
(if (list? (car args))
|
||||
#`(syntax-rules ... #,@args)
|
||||
(let ((ellipsis (car args))
|
||||
(literals (car (cdr args)))
|
||||
(rules (cdr (cdr args))))
|
||||
(compile ellipsis literals rules))))
|
||||
|
||||
(let ((form (normalize-form form)))
|
||||
(if form
|
||||
(let ((ellipsis (list-ref form 1))
|
||||
(literals (list-ref form 2))
|
||||
(rules (list-tail form 3)))
|
||||
(let ((clauses (map (lambda (rule) (compile-rule ellipsis literals rule))
|
||||
rules)))
|
||||
`(,_er-macro-transformer
|
||||
(,_lambda (expr rename cmp)
|
||||
,(expand-clauses clauses r)))))
|
||||
|
||||
`(,_syntax-error "malformed syntax-rules"))))))
|
||||
|
||||
(export syntax-rules
|
||||
_
|
||||
|
|
|
|||
Loading…
Reference in New Issue