[racket] parser-tools help

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On 30-11-11 14:33, Marijn wrote:
> Hi,
> 
> I'm trying to use the parser-tools to parse the startup info for
> the Google AI Challenge, but I am not sure what I'm doing wrong.

I managed to get my code working, see below. (BTW parser gives a
really silly error-message when you have an end-clause like (end 'ready).)

> As a secondary question, given the repetitive nature of the code,
> how would one use macros to make it better?

I'd still be interested in how to do this.

Marijn


#lang racket

(require parser-tools/lex
         (prefix-in re: parser-tools/lex-sre)
         parser-tools/yacc)

(define-tokens number-group (number))

(define-tokens turn0-data-group
  (turn
   loadtime
   turntime
   rows
   cols
   turns
   viewradius2
   attackradius2
   spawnradius2
   player_seed))

(define-empty-tokens turn0-end-group (ready))

(define (turn0-lexer port)
  ((lexer
   ("turn" 'turn)
   ("loadtime" 'loadtime)
   ("turntime" 'turntime)
   ("rows" 'rows)
   ("cols" 'cols)
   ("turns" 'turns)
   ("viewradius2" 'viewradius2)
   ("attackradius2" 'attackradius2)
   ("spawnradius2" 'spawnradius2)
   ("player_seed" 'player_seed)
   ("ready" 'ready)
   ((re:+ (char-set "1234567890")) (token-number lexeme))
   ((re:+ whitespace) (turn0-lexer port))
   )
   port) )

(define turn0-parser
  (let ((ret (hash)))
    (parser
     (tokens number-group turn0-data-group turn0-end-group)
     (start data)
     (end ready)
     (grammar
      (data ((datum) (hash (token-name $1) (token-value $1)))
	    ((datum data) (hash-set $2 (token-name $1) (token-value $1)))
	    )
      (datum ((turn number) (token-turn $2))
	     ((loadtime number) (token-loadtime $2))
	     ((turntime number) (token-turntime $2))
	     ((rows number) (token-rows $2))
	     ((cols number) (token-cols $2))
	     ((turns number) (token-turns $2))
	     ((viewradius2 number) (token-viewradius2 $2))
	     ((attackradius2 number) (token-attackradius2 $2))
	     ((spawnradius2 number) (token-spawnradius2 $2))
	     ((player_seed number) (token-player_seed $2))
	     )
      )
     (error (lambda args (map displayln args))) )) )
	
(define (main port)
  (write (turn0-parser (lambda () (turn0-lexer port)))))

(define input
  (string-append
   "turn 0 "
   "loadtime 3000"
   "turntime 1000"
   "rows 20  "
   "cols 20  "
   "turns 500  "
   "viewradius2 55  "
   "attackradius2 5  "
   "spawnradius2 1  "
   "player_seed 42"
   "ready") )

(main (open-input-string input))
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