lex bug ?
Michael Henning
michi at anvil.oz
Fri Mar 31 16:35:08 AEST 1989
I came across the following today. The problems show up both under AIX and
Xenix. Could anyone please enlighten me as to whether these are real bugs
or am I just overlooking something ?
Problem 1:
The following lex input file recognizes comments as a '*' at the beginning
of a line followed by any number of characters to the end of the line:
%%
^\*.*$ printf("comment: %s\n", yytext);
If the file is changed to
comment ^\*.*$
%%
{comment} printf("comment: %s\n", yytext);
then comments are no longer recognised.
Problem 2:
The following lex input file is supposed to recognize empty lines.
{empty_line} ^$
%%
{empty_line} printf("empty line\n");
The program compiles, but does not recognize empty lines. If the program
is changed to
%%
^$ printf("empty line\n");
then lex reports a syntax error on line 2.
Any help on these would be greatly appreciated, I have not used lex before,
and the documentation is somewhat terse in places...
Michi.
--
| The opinions expressed are my own, not those of my employer. |
| |
| Michael (Michi) Henning |
| - We have three Michaels here, that's why they call me Michi |
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