Lex and Yacc are maintained by the Unix SVRx licencees - companies such as IBM (AIX), HP (HP-UX) and Sun (Solaris) have modified versions of Lex and Yacc at their command. MKS also provides MKS Lex and MKS Yacc; however, the Yacc at least has some non-standard extensions. Flex and Bison are free. (AT&T) Lex and Yacc are not.

Sep 24, 2015 · So I would like to know features GNU bison has that the original yacc is missing. The reason I get worried is because I noticed that my parser failed to compile on Windows using a bison port. I would sacrifice GNU bison features and stick with the original standardized yacc if it would make my parser easier to port between different platforms.

Jul 5, 2011 · I'm not an expert at yacc, but the way I've been handling the transition from the lexer to the parser is as follows: for each lexer token, you should have a separate rule to "translate" the yytext into a suitable form for your parser.

Mar 28, 2011 · After that, set the PATH variable to include the bin directories of gcc (in C:\Dev-Cpp\bin) and flex\bison (in C:\GnuWin32\bin). To do that, copy this: ;C:\Dev-Cpp\bin;C:\GnuWin32\bin and append it to the end of the PATH variable, defined in the place show by this figure:

The most significant difference between YACC/Bison and ANTLR is the type of grammars these tools can process. YACC/Bison handle LALR grammars, ANTLR handles LL grammars. Often, people who have worked with LALR grammars for a long time, will find working with LL grammars more difficult and vice versa.

Mar 10, 2016 · However, Bison is intended to be a reliable program that conforms to the POSIX specification for Yacc. If you run into problems, please send us a bug report. Yacc Warnings. In the past there was little interest from users in the accuracy of the option -Wyacc. In fact, this very question on StackOverflow was not asked on the Bison bug report list.

Dec 2, 2008 · For many years the de facto tool for generating code to parse a grammar was yacc, or its GNU cousin, bison. Lately I've heard there are a couple of new kids on the block, but the principle is the same: you write a declarative grammar in a format that is more or less in Backus-Naur Form ( BNF ) and yacc/bison/whatever generates some code for you ...

Nov 18, 2009 · If you use C Bizon (not C++), just use END for token::END and in yacc file %token END Had another issue after that, if the macros return not YY_NULL, it never terminates (infinite loop) It can be solved like this:

Oct 31, 2014 · The fact that in "real world grammars" (Yacc, Bison, etc.) this empty right-hand side part of the rule is not explicitly marked as empty troubles me: it is easy to miss the fact that an rhs is empty, or worse: to forget to insert | and actually use a mid-rule action:

May 24, 2012 · Since bison is supposed to be compatible with yacc so the first thing I would try would be: alias yacc="bison" and try again. On my setup, /usr/bin/yacc is simply a script containing: #! /bin/sh exec '/usr/bin/bison' -y "$@" You can try to locate the yacc or bison executables with the command (substituting bison for yacc if need be): which yacc