parsing - Basic problem with yacc/lex -

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I have some problems with a very simple yacc / lex program. I have probably forgotten some basic steps (when I have used these tools since then it has been a long time).

In my Lex program, I have some basic values ​​like: 

  word [a-zA-Z] [a-zA-Z] * %% ":" Return (PV); {Word} {Yiwal = yatex; Printf ("yylval =% s \ n", yellow); Return (word); } "\ N" return (ENDLINE);

In my yacc program is the beginning of my grammar (where the translation UIT is my% beginning): 

  Translation: / * nothing * / | InfoBlock data; InfoBlock: / * None * / | InfoBlock InfoExpression {}; Information Expression: Word PV Word Endline {printf ("$ 1 =% s \ n", $ 1); Printf ("$ 2 =% s \ n", $ 2); Printf ("$ 3 =% s \ n", $ 3); Printf ("$ 4 =% s \ n", $ 4); } | ... /* other things */             ; Data: ... / * Other Things * /

When I run my program with input: 

  keyword: value  < / Pre> 
 I thought I would get the least: 
 
  $ 1 = keyword $ 2 = keyword // do not change yylval for tokoni $ 3 = value $ 4 = value / Not really changed to Yolwel token:  
  $ 1 = keyword: value $ 2 = keyword: value $ 3 = value $ 4 = value

I do not understand the result I had some time ago Studied extracts and even if I do not remember everything, so I have no significant fault ...

Thanks in advance for your help.

The problem is that unless you do not save the token, overwriting Lex / Wide Space Goes for, or points to a different place, etc. Before it is modified, you need to hide important information. Your printing in Lex Code should show you that yylval values ​​were exact at that point when

See also that the same basic problem was encountered and diagnosed.


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