bison

I'm trying to make a Bison parser to handle UTF-8 characters. I don't want the parser to actually interpret the Unicode character values, but I want it to parse the UTF-8 string as a sequence of bytes. Right now, Bison generates the following code which is problematic: if (yychar <= YYEOF) { yychar = yytoken = YYEOF; YYDPRINTF ((stderr, "Now at end of input.\n")); } The problem is that many bytes of the UTF-8 string will have a negative value, and Bison interprets negative values as an EOF, and stops. Is there a way around this? bison yes, flex no. The one time I needed a bison parser to work

I'm using bison & flex (downloaded via cygwin) with vc++. When I compile the program I got an error: ...: fatal error C1083: Cannot open include file: 'unistd.h': No such file or directory The corresponding code in the flex-generated file is: #ifndef YY_NO_UNISTD_H /* Special case for "unistd.h", since it is non-ANSI. We include it way * down here because we want the user's section 1 to have been scanned first. * The user has a chance to override it with an option. */ /* %if-c-only */ #include <unistd.h> /* %endif */ /* %if-c++-only */ /* %endif */ #endif If I define YY_NO_UNISTD_H in the flex

I would like to create my own programming language. Maybe not exactly a programming language from scratch but maybe base it on another language. I've heard of Yacc. So, I installed Flex and Bison. But I do not understand how to make a compiler with it. I have made the Hello world project in it, but how would I make a compiler in it? Are there any easy ways of creating a small programming language, I have heard of translating a language as in taking, e.g., Write() and making the computer understand it as Print() . Is this be possible?. My take on this is that the simpler approach is not to mess

Running Bison on this file: %{ #include <iostream> int yylex(); void yyerror(const char*); %} %union { char name[100]; int val; } %token NUM ID %right '=' %left '+' '-' %left '*' %% exp : NUM {$$.val = $1.val;} | ID {$$.val = vars[$1.name];} | exp '+' exp {$$.val = $1.val + $3.val;} | ID '=' exp {$$.val = vars[$1.name] = $3.val;} ; %% Leads to warnings of the kind of: warning: $$ of 'exp' has no declared type. What does it mean and how do I solve it? Asaf R The union (%union) defined is not intended to be used directly. Rather, you need to tell Bison which member of the union is used by which

I'm attempting to learn some flex/bison, and I'm reading Flex & Bison by John Levine (O'Reilly). There is an example that I need to get running, however I can't get it to run as I get the following error: /tmp/ccKZcRYB.o: In function `yylex': fb3-1.lex.c:(.text+0x2bd): undefined reference to `yylval' /tmp/cclBqnOk.o: In function `main': fb3-1funcs.c:(.text+0x420): undefined reference to `yyparse' collect2: ld returned 1 exit status I've got four source files: fb3-1.h : /* * Declarations for calculator fb3-1 */ /* Interface to the lexer */ extern int yylineno; /* from lexer */ void yyerror(char