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I've got some errors in my lex code, maybe someone know what i made wrong ...

16    %%
17    {ws}  {/*no action and no return */}
18    {}    
19    {newline} {lineo++;}
20    {number}  {tokenval=atoi(yytext); return(NUM);}
21    {id}      {
22          int p = 0;
23          p = lookup(yytext);
24          if (p == 0) 
25          p = insert (yytext, ID);
26      tokenval = p;
27      return symtable[p].token;
28    
29    }
30    
31    <<EOF>>   {return DONE;}
32      {tokenval = NONE; return yytext[0];}
33    
34    
35    %%

I'm newbie in this kind of technology, and I spend on it many of time but without any positive result. Below errors from the console:

new.l:21: unrecognized rule
new.l:28: unrecognized rule
new.l:28: unrecognized rule
new.l:36: EOF encountered inside an action
new.l:36: unrecognized rule
new.l:36: fatal parse error
make: *** [lex.yy.c] Error 1

When I'm deleted that lines of code whoes bad (lines: 21-32) I've got that error:

new.l:19:2: error: ‘lineo’ undeclared (first use in this function) {newline} {lineo++;}

Epredator
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1 Answers1

3

  1. Line 18 ({}) is just wrong; flex will treat that as a pattern, not an action.

  2. You probably meant to write lineno (that is, a way of typing "Line Nº" which is an abbreviation for "line number".) But did you declare it somewhere? Or did you intend to use yylineno?

  3. Did you define {id}? The error message suggests you didn't, but you didn't paste your definitions.

  4. In line 32, the pattern for the default rule is .:

    . {tokenval = NONE; return yytext[0];}

  5. Have you read the handy flex manual?

In addition to the above, as a replacement to point 3, the definition:

id      {letter}({letter} | {digit})*

is incorrect because regular expressions cannot include unquoted whitespace. You need to write that as

id      {letter}({letter}|{digit})*
rici
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  • This is all my code: https://gist.github.com/Epredator/11263395 . I was trying make some changes, but I still have no idea how it works. I use this manual to Flex: http://neo.dmcs.p.lodz.pl/tk/flex/flex.pdf maybe is not new version but still works ;) – Epredator Apr 24 '14 at 17:49
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    @Epredator: I added one more error to correct. Also, your final code block is not valid `C` because the function `lexan` you define doesn't have an explicit return type; it probably should have been written `int lexan() { return yylex(); }` but it's redundant because you can just call `yylex` directly. The manual is indeed for an older version, and I'd recommend using a newer one such as the one I linked to. But it should be ok. – rici Apr 24 '14 at 18:05