CODEWITHSUNDEEP
c++flex-lexer
Shuvo
Shuvo

Reputation: 113

C++ multiline comment syntax in flex

I have a problem with my flex script. I write it for C++ multiline comment. My flex pattern is:

"/""*"[^"*""/"]*"*""/"          {strcpy(mlc[mlc_count++],yytext);}

It can find one multiline comment. But when I put entire code in multiline comment it doesn't work. I tried lot but can't find any solution.

Upvotes: 1

Views: 1040

Answers (1)

Jerry Coffin
Jerry Coffin

Reputation: 490108

Flex reads input one buffer at a time. Using normal matching, a single token can occupy no more than one buffer of data. If memory serves, the buffer is normally something like 8 kilobytes, so a single token longer than that won't match correctly.

Typically you work around this with an exclusive start condition, something on this general order:

"/*" BEGIN(COMMENT); 

<COMMENT>*/ BEGIN(INITIAL);
<COMMENT>.  { current_comment += yytext[0]; }

Upvotes: 1

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