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beautiful-racket/beautiful-racket-ragg/br/ragg/rules/stx.rkt

79 lines
3.4 KiB
Racket

#lang racket/base
(require "rule-structs.rkt"
parser-tools/lex
racket/match
syntax/strip-context)
(provide rules->stx)
;; Given a sequence of rules, we translate these to syntax objects.
;; rules->stx: (listof rule) -> syntax
(define (rules->stx source rules #:original-stx [original-stx #f])
(define rule-stxs
(map (lambda (stx) (rule->stx source stx))
rules))
(datum->syntax #f
`(rules ,@rule-stxs)
original-stx))
(define (rule->stx source a-rule)
(define id-stx
(datum->syntax #f
(string->symbol (lhs-id-val (rule-lhs a-rule)))
(list source
(pos-line (lhs-id-start (rule-lhs a-rule)))
(pos-col (lhs-id-start (rule-lhs a-rule)))
(pos-offset (lhs-id-start (rule-lhs a-rule)))
(if (and (number? (pos-offset (lhs-id-start (rule-lhs a-rule))))
(number? (pos-offset (lhs-id-end (rule-lhs a-rule)))))
(- (pos-offset (lhs-id-end (rule-lhs a-rule)))
(pos-offset (lhs-id-start (rule-lhs a-rule))))
#f))))
(define pattern-stx (pattern->stx source (rule-pattern a-rule)))
(define line (pos-line (rule-start a-rule)))
(define column (pos-col (rule-start a-rule)))
(define position (pos-offset (rule-start a-rule)))
(define span (if (and (number? (pos-offset (rule-start a-rule)))
(number? (pos-offset (rule-end a-rule))))
(- (pos-offset (rule-end a-rule))
(pos-offset (rule-start a-rule)))
#f))
(datum->syntax #f
`(rule ,id-stx ,pattern-stx)
(list source line column position span)))
(define (pattern->stx source a-pattern)
(define recur (lambda (s) (pattern->stx source s)))
(define line (pos-line (pattern-start a-pattern)))
(define column (pos-col (pattern-start a-pattern)))
(define position (pos-offset (pattern-start a-pattern)))
(define span (if (and (number? (pos-offset (pattern-start a-pattern)))
(number? (pos-offset (pattern-end a-pattern))))
(- (pos-offset (pattern-end a-pattern))
(pos-offset (pattern-start a-pattern)))
#f))
(define source-location (list source line column position span))
(datum->syntax #f
(match a-pattern
[(struct pattern-id (start end val))
`(id ,(datum->syntax #f (string->symbol val) source-location))]
[(struct pattern-lit (start end val))
`(lit ,(datum->syntax #f val source-location))]
[(struct pattern-token (start end val))
`(token ,(datum->syntax #f (string->symbol val) source-location))]
[(struct pattern-choice (start end vals))
`(choice ,@(map recur vals))]
[(struct pattern-repeat (start end min val))
`(repeat ,min ,(recur val))]
[(struct pattern-maybe (start end val))
`(maybe ,(recur val))]
[(struct pattern-seq (start end vals))
`(seq ,@(map recur vals))]
[(struct pattern-elide (start end vals))
`(elide ,@(map recur vals))])
source-location))