You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
brag/parser-tools/private-lex/token.rkt

81 lines
2.6 KiB
Racket

#lang racket/base
(require (for-syntax racket/base yaragg/parser-tools/private-lex/token-syntax))
;; Defining tokens
(provide define-tokens define-empty-tokens token token?
(protect-out (rename-out [token-name real-token-name]))
(protect-out (rename-out [token-value real-token-value]))
(rename-out [token-name* token-name][token-value* token-value])
(struct-out position)
(struct-out position-token)
(struct-out srcloc-token))
;; A token is either
;; - symbol
;; - (token symbol any)
(struct token (name value) #:transparent)
;; token-name*: token -> symbol
(define (token-name* t)
(cond
[(symbol? t) t]
[(token? t) (token-name t)]
[else (raise-type-error 'token-name "symbol or struct:token" 0 t)]))
;; token-value*: token -> any
(define (token-value* t)
(cond
[(symbol? t) #f]
[(token? t) (token-value t)]
[else (raise-type-error 'token-value "symbol or struct:token" 0 t)]))
(define-for-syntax (make-ctor-name n)
(datum->syntax n
(string->symbol (format "token-~a" (syntax-e n)))
n
n))
(define-for-syntax ((make-define-tokens empty?) stx)
(syntax-case stx ()
[(_ NAME (TOKEN ...))
(andmap identifier? (syntax->list #'(TOKEN ...)))
(with-syntax (((marked-token ...)
(map values #;(make-syntax-introducer)
(syntax->list #'(TOKEN ...)))))
(quasisyntax/loc stx
(begin
(define-syntax NAME
#,(if empty?
#'(e-terminals-def (quote-syntax (marked-token ...)))
#'(terminals-def (quote-syntax (marked-token ...)))))
#,@(map
(λ (n)
(when (eq? (syntax-e n) 'error)
(raise-syntax-error
#f
"Cannot define a token named error."
stx))
(if empty?
#`(define (#,(make-ctor-name n))
'#,n)
#`(define (#,(make-ctor-name n) x)
(token '#,n x))))
(syntax->list #'(TOKEN ...)))
#;(define marked-token #f) #;...)))]
[(_ ...)
(raise-syntax-error #f
"must have the form (define-tokens name (identifier ...)) or (define-empty-tokens name (identifier ...))"
stx)]))
(define-syntax define-tokens (make-define-tokens #f))
(define-syntax define-empty-tokens (make-define-tokens #t))
(struct position (offset line col) #:inspector #f)
(struct position-token (token start-pos end-pos) #:inspector #f)
(struct srcloc-token (token srcloc) #:inspector #f)