br-parser-tools/collects/parser-tools/yacc.ss

#cs
(module yacc mzscheme

  (require-for-syntax "private-yacc/parser-builder.ss"
                      "private-yacc/yacc-helper.ss")
  (require "private-yacc/terminal.ss" 
           "private-yacc/parser-actions.ss"
           "private-yacc/array2d.ss")
  
  (provide define-tokens define-empty-tokens parser)

  (define-syntax parser
    (lambda (stx)
      (syntax-case stx ()
	((_ args ...)
         (let ((arg-list (syntax->list (syntax (args ...))))
               (debug #f)
               (error #f)
               (tokens #f)
               (start #f)
               (end #f)
               (precs #f)
               (grammar #f))
           (for-each
            (lambda (arg)
              (syntax-case arg (debug error tokens start end precs grammar)
                ((debug filename)
                 (cond
                   ((not (string? (syntax-object->datum (syntax filename))))
                    (raise-syntax-error 
                     'parser-debug
                     "Debugging filename must be a string"
                     (syntax filename)))
                   (debug
                    (raise-syntax-error #f "Multiple debug declarations" stx))
                   (else
                    (set! debug (syntax-object->datum (syntax filename))))))
                ((error expression)
                 (if error
                     (raise-syntax-error #f "Multiple error declarations" stx)
                     (set! error (syntax expression))))
                ((tokens def ...)
                 (if tokens
                     (raise-syntax-error  #f "Multiple tokens declarations" stx)
                     (set! tokens arg)))
                ((start symbol)
                 (cond
                   ((not (identifier? (syntax symbol)))
                    (raise-syntax-error
                     'parser-start
                     "Start non-terminal must be a symbol"
                     (syntax symbol)))
                   (start
                    (raise-syntax-error #f "Multiple start declarations" stx))
                   (else
                    (set! start (syntax symbol)))))
                ((end symbols ...)
                 (begin
                   (for-each
                    (lambda (sym)
                      (if (not (identifier? sym))
                          (raise-syntax-error
                           'parser-end
                           "End token must be a symbol"
                           sym)))
                    (syntax->list (syntax (symbols ...))))
                   (let ((d (duplicate-list? (syntax-object->datum 
                                              (syntax (symbols ...))))))
                     (if d
                         (raise-syntax-error
                          'parser-end
                          (format "Duplicate end token definition for ~a" d)
                          arg)))
                   (if (= 0 (length (syntax->list (syntax (symbols ...)))))
                       (raise-syntax-error
                        'parser-end
                        "end declaration must contain at least 1 token"
                        arg))
                   (if end
                       (raise-syntax-error #f "Multiple end declarations" stx))
                   (set! end (syntax->list (syntax (symbols ...))))))
                ((precs decls ...)
                 (if precs
                     (raise-syntax-error #f "Multiple precs declarations" stx)
                     (set! precs arg)))
                ((grammar prods ...)
                 (if grammar
                     (raise-syntax-error #f "Multiple grammar declarations" stx)
                     (set! grammar arg)))
                (_ (raise-syntax-error 'parser-args "argument must match (debug filename), (error expression), (tokens def ...), (start non-term), (end tokens ...), (precs decls ...), or  (grammar prods ...)" arg))))
            (syntax->list (syntax (args ...))))
           (if (not tokens)
               (raise-syntax-error #f "missing tokens declaration" stx))
           (if (not error)
               (raise-syntax-error #f "missing error declaration" stx))
           (if (not grammar)
               (raise-syntax-error #f "missing grammar declaration" stx))
           (if (not end)
               (raise-syntax-error #f "missing end declaration" stx))
           (build-parser (if debug debug "")
                         error
                         tokens
                         start
                         end
                         precs
                         grammar
                         #'here
                         stx)))
        (_
         (raise-syntax-error
          #f
          "parser must have the form (parser args ...)"
          stx)))))
  

)