preserves/implementations/racket/preserves/preserves-schema/parser.rkt

109 lines
4.4 KiB
Racket

#lang racket/base
(provide definition-parser)
(require preserves)
(require racket/match)
(require (only-in racket/syntax format-symbol))
(require "type.rkt")
(define (definition-parser name def)
(define ty (definition-ty def))
`(define (,(format-symbol "parse-~a" name) input)
,(match def
[(record 'or (list named-alts))
`(match input
,@(for/list [(named-alt (in-list named-alts))
(alt-ty (in-list (map cadr (ty-union-variants ty))))]
(match-define (list variant-label-str pattern) named-alt)
`[,(pattern->match-pattern pattern 'dest)
,(construct (format-symbol "~a-~a" name variant-label-str) #t alt-ty)])
[_ eof])]
[(record 'and (list named-pats))
`(match input
[(and ,@(for/list [(named-pat named-pats)] (pattern->match-pattern named-pat '_)))
,(construct name #f ty)]
[_ eof])]
[pattern
`(match input
[,(pattern->match-pattern pattern 'dest)
,(construct name #f ty)]
[_ eof])])))
(define (construct name wrap? ty)
(match ty
[(ty-record fields) `(,name ,@(map escape (map car fields)))]
[(ty-unit) (if wrap? `(,name) `(void))]
[_ (if wrap? `(,name dest) 'dest)]))
(define (maybe-dest dest-pat-stx pat)
(match dest-pat-stx
['_ pat]
[_ `(and ,dest-pat-stx ,pat)]))
(define (pattern->match-pattern pattern dest-pat-stx)
(match pattern
[(record 'named (list n p)) (pattern->match-pattern p (maybe-dest dest-pat-stx (escape n)))]
['any dest-pat-stx]
[(record 'atom (list atom-kind))
(maybe-dest dest-pat-stx
`(? ,(match atom-kind
['Boolean 'boolean?]
['Float 'float?]
['Double 'flonum?]
['SignedInteger 'integer?]
['String 'string?]
['ByteString 'bytes?]
['Symbol 'symbol?])))]
[(record 'embedded '()) (error 'pattern-parser "Embedded not yet implemented")]
[(record 'lit (list v)) (maybe-dest dest-pat-stx (literal->pattern v))]
[(record 'ref (list '() name))
`(app ,(format-symbol "parse-~a" name) ,(maybe-dest dest-pat-stx `(not (== eof))))]
[(record 'ref (list module-path name))
(error 'pattern-parser "Ref with non-empty module path not yet implemented")]
[(record 'tuple* (list '() (and variable-pat (not (record 'named _)))))
`(parse-sequence list?
values
,(pattern->match-pattern variable-pat 'item)
item
values
,dest-pat-stx)]
[(record 'setof (list pat))
`(parse-sequence set?
set->list
,(pattern->match-pattern pat 'item)
item
list->set
,dest-pat-stx)]
[(record 'dictof (list key-pat value-pat))
`(parse-sequence dict?
dict->list
(cons ,(pattern->match-pattern key-pat 'key)
,(pattern->match-pattern value-pat 'value))
(cons key value)
make-immutable-hash
,dest-pat-stx)]
[(record 'rec (list label-pat fields-pat))
(maybe-dest dest-pat-stx `(record ,(pattern->match-pattern label-pat '_)
,(pattern->match-pattern fields-pat '_)))]
[(record 'tuple (list named-pats))
(maybe-dest dest-pat-stx
`(list ,@(map (lambda (p) (pattern->match-pattern p '_)) named-pats)))]
[(record 'tuple* (list fixed-named-pats (record 'named (list vname vpat))))
(maybe-dest dest-pat-stx
`(list* ,@(map (lambda (p) (pattern->match-pattern p '_)) fixed-named-pats)
(list ,(pattern->match-pattern vpat (escape vname)) ...)))]
[(record 'dict (list (hash-table (keys pats) ...)))
(maybe-dest dest-pat-stx
`(hash-table ,@(for/list [(key (in-list keys))
(pat (in-list pats))]
`(,(literal->pattern key)
,(pattern->match-pattern (add-name-if-absent key pat) '_)))
(_ _) ...))]))
(define (literal->pattern v)
(if (symbol? v)
`',v
`(== ',v)))