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Questions - yacc

Understanding how to resolve reduce/reduce & shift/reduce conflicts

I have the following tokens, operator precedence and grammar rules in my parser.y file: %token <intval> INTCONST %token <realval> REALCONST %token <strval> STRCONST %token <strval...
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Stelios Papamichail

c

bison

yacc

Votes: 0

Answers: 1

Latest Answer

If I'm understanding things correctly, the parser has already seen the BRACK_L token and is now at the cursor (dot) location. If the next token that he sees is any of the following (BRACK_R, MIN, CBR...
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Pax

How does Bison deal with some optional part in BNF grammars?

I'm a freshman in Bison and Compiler principles, now I'm trying to write an easy Verilog parser in Flex&Bison according to the IEEE Standard. Here is the question: when a grammar's body has option...
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Zhiyi

parsing

flexbox

bison

yacc

Votes: 0

Answers: 1

Latest Answer

The best solution is (2): net_type: %empty | ...; signed: %empty | ...; range: %empty | ...; You should not see any conflicts between them unless they share tokens. If you attempted to write all...
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Pax

How to replace a lexer token with two new tokens?

In XML an empty element can be represented in either of these ways: <foo></foo> <foo/> If the input contains the latter, then I want to tokenize it like the former. That is, if the ...
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Roger Costello

bison

flex-lexer

yacc

lex

Votes: 0

Answers: 1

Latest Answer

After the returning statement return(">"); you don't execute anything else. Also, changing the internal variable yytext with yytext = ">"; is never a good idea. First strdup(...
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Pax

Lexer that can be used in debug mode or in operational mode

I am reading a book that has a nifty way of designing a lexer so that, when DEBUG is defined, it outputs token is value for each token. I have a simple lexer that has a rule for a NAME and a rule for ...
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Roger Costello

bison

flex-lexer

yacc

lex

Votes: 0

Answers: 1

Latest Answer

After looking at a footnote in the book, I discovered the correct approach. It is wicked cool. See code below. %option noyywrap %{ #ifdef DEBUG int yylex(void); char * yylval; int main(in...
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Roger Costello

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