Hello,
I'm writing a literate program which includes a lexer/parser.
I am trying to build up the lexer a token at a time...
---------
#lang scribble/lp
@section{newlines}
A newline is at the end of a line... in fact we'll consume all newlines,
since we don't care how many there are.
@chunk[<empty-tokens> new-line]
@chunk[<lex-rules> ((:+ (:or #\newline #\return)) (token-new-line))]
@section{End of file}
The parser would like to know when I've run out of file...
@chunk[<empty-tokens> end-of-file]
@chunk[<lex-rules> ((eof) (token-end-of-file))]
@chunk[<*>
(define-empty-tokens mt-token-group (<empty-tokens>))
]
-------------
Upon requiring this module; I get:
"lex-lp.rkt:5:22: compile: unbound identifier in module in: new-line"
Should I be able to do this? Should the LP code replace <*> with:
(define-empty-tokens mt-token-group (new-line end-of-file))
and then evaluate it?
Or am I doing something horribly wrong (again).
Regards,
Tim
--
Tim Brown <tim.br...@cityc.co.uk> | City Computing Limited |
T: +44 20 8770 2110 | City House, Sutton Park Road |
F: +44 20 8770 2130 | Sutton, Surrey, SM1 2AE, GB |
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