racket/collects/scheme/match/parse.ss
2008-05-26 19:51:06 +00:00

176 lines
6.5 KiB
Scheme

#lang scheme/base
(require syntax/boundmap
syntax/stx
scheme/struct-info
"patterns.ss"
"compiler.ss"
"parse-helper.ss"
"parse-quasi.ss"
(only-in srfi/1 delete-duplicates)
(for-template (only-in "runtime.ss" matchable?)
scheme/base))
(provide parse/cert)
(define (ht-pat-transform p)
(syntax-case p ()
[(a b) #'(list a b)]
[x (identifier? #'x) #'x]))
;; parse : syntax -> Pat
;; compile stx into a pattern, using the new syntax
(define (parse/cert stx cert)
(define (parse stx) (parse/cert stx cert))
(syntax-case* stx (not var struct box cons list vector ? and or quote app
regexp pregexp list-rest list-no-order hash-table
quasiquote mcons list* mlist)
(lambda (x y) (eq? (syntax-e x) (syntax-e y)))
[(expander args ...)
(and (identifier? #'expander)
(match-expander? (syntax-local-value (cert #'expander)
(lambda () #f))))
(match-expander-transform
parse/cert cert #'expander stx match-expander-match-xform
"This expander only works with the legacy match syntax")]
[(var v)
(identifier? #'v)
(make-Var #'v)]
[(and p ...)
(make-And (map parse (syntax->list #'(p ...))))]
[(or p ...)
(let ([ps (map parse (syntax->list #'(p ...)))])
(all-vars ps stx)
(make-Or ps))]
[(not p ...)
;; nots are conjunctions of negations
(let ([ps (map (compose make-Not parse) (syntax->list #'(p ...)))])
(make-And ps))]
[(regexp r)
(trans-match #'matchable?
#'(lambda (e) (regexp-match r e))
(make-Pred #'values))]
[(regexp r p)
(trans-match #'matchable? #'(lambda (e) (regexp-match r e)) (parse #'p))]
[(pregexp r)
(trans-match #'matchable?
#'(lambda (e)
(regexp-match (if (pregexp? r) r (pregexp r)) e))
(make-Pred #'values))]
[(pregexp r p)
(trans-match #'matchable?
#'(lambda (e)
(regexp-match (if (pregexp? r) r (pregexp r)) e))
(parse #'p))]
[(box e) (make-Box (parse #'e))]
[(vector es ...)
(ormap ddk? (syntax->list #'(es ...)))
(trans-match #'vector?
#'vector->list
(parse (syntax/loc stx (list es ...))))]
[(vector es ...)
(make-Vector (map parse (syntax->list #'(es ...))))]
[(hash-table p ... dd)
(ddk? #'dd)
(trans-match
#'hash?
#'(lambda (e) (hash-map e list))
(with-syntax ([(elems ...)
(map ht-pat-transform (syntax->list #'(p ...)))])
(parse (syntax/loc stx (list-no-order elems ... dd)))))]
[(hash-table p ...)
(ormap ddk? (syntax->list #'(p ...)))
(raise-syntax-error
'match "dot dot k can only appear at the end of hash-table patterns" stx
(ormap (lambda (e) (and (ddk? e) e)) (syntax->list #'(p ...))))]
[(hash-table p ...)
(trans-match #'hash?
#'(lambda (e) (hash-map e list))
(with-syntax ([(elems ...)
(map ht-pat-transform
(syntax->list #'(p ...)))])
(parse (syntax/loc stx (list-no-order elems ...)))))]
[(hash-table . _)
(raise-syntax-error 'match "syntax error in hash-table pattern" stx)]
[(list-no-order p ... lp dd)
(ddk? #'dd)
(let* ([count (ddk? #'dd)]
[min (if (number? count) count #f)]
[max (if (number? count) count #f)]
[ps (syntax->list #'(p ...))])
(make-GSeq (cons (list (parse #'lp))
(for/list ([p ps]) (list (parse p))))
(cons min (map (lambda _ 1) ps))
(cons max (map (lambda _ 1) ps))
;; vars in lp are lists, vars elsewhere are not
(cons #f (map (lambda _ #t) ps))
(make-Null (make-Dummy (syntax/loc stx _)))
#f))]
[(list-no-order p ...)
(ormap ddk? (syntax->list #'(p ...)))
(raise-syntax-error
'match "dot dot k can only appear at the end of unordered match patterns"
stx
(ormap (lambda (e) (and (ddk? e) e)) (syntax->list #'(p ...))))]
[(list-no-order p ...)
(let ([ps (syntax->list #'(p ...))])
(make-GSeq (for/list ([p ps]) (list (parse p)))
(map (lambda _ 1) ps)
(map (lambda _ 1) ps)
;; all of these patterns get bound to only one thing
(map (lambda _ #t) ps)
(make-Null (make-Dummy (syntax/loc stx _)))
#f))]
[(list) (make-Null (make-Dummy (syntax/loc stx _)))]
[(mlist) (make-Null (make-Dummy (syntax/loc stx _)))]
[(list ..)
(ddk? #'..)
(raise-syntax-error 'match "incorrect use of ... in pattern" stx #'..)]
[(mlist ..)
(ddk? #'..)
(raise-syntax-error 'match "incorrect use of ... in pattern" stx #'..)]
[(list p .. . rest)
(ddk? #'..)
(dd-parse parse #'p #'.. (syntax/loc stx (list . rest)))]
[(mlist p .. . rest)
(ddk? #'..)
(dd-parse parse #'p #'.. (syntax/loc stx (list . rest)) #:mutable #t)]
[(list e es ...)
(make-Pair (parse #'e) (parse (syntax/loc stx (list es ...))))]
[(mlist e es ...)
(make-MPair (parse #'e) (parse (syntax/loc stx (mlist es ...))))]
[(list* . rest)
(parse (syntax/loc stx (list-rest . rest)))]
[(list-rest e)
(parse #'e)]
[(list-rest p dd . rest)
(ddk? #'dd)
(dd-parse parse #'p #'dd (syntax/loc stx (list-rest . rest)))]
[(list-rest e . es)
(make-Pair (parse #'e) (parse (syntax/loc #'es (list-rest . es))))]
[(cons e1 e2) (make-Pair (parse #'e1) (parse #'e2))]
[(mcons e1 e2) (make-MPair (parse #'e1) (parse #'e2))]
[(struct s pats)
(parse-struct stx cert parse #'s #'pats)]
[(? p q1 qs ...)
(make-And (cons (make-Pred (cert #'p))
(map parse (syntax->list #'(q1 qs ...)))))]
[(? p)
(make-Pred (cert #'p))]
[(app f p)
(make-App #'f (parse (cert #'p)))]
[(quasiquote p)
(parse-quasi #'p cert parse/cert)]
[(quasiquote . _)
(raise-syntax-error 'match "illegal use of quasiquote")]
[(quote . _)
(parse-quote stx parse)]
[x
(identifier? #'x)
(parse-id #'x)]
[v
(or (parse-literal (syntax-e #'v))
(raise-syntax-error 'match "syntax error in pattern" stx))]))
;; (trace parse)