bison

I am using Bison with Flex. I have the following rule in my Yacc input file: program : PROGRAM m2 declarations m0 block {cout << "Success\n"} ; The problem is that if I have a program that is partially correct, but then there is some "garbage" before EOF, it will reduce according to the previous rule, report "success" and only then report an error. I want to include EOF at the end of the rule above, but then, Flex would have to return EOF when it read <<EOF>> , and how would Bison know when to end the program? Now, I have this in Flex: <<EOF>> {return 0;} Here is an example that would do that:

I would like to understand why BISON is concatenating two tokens on the following rule stmt: declaration { ... } | assignment { ... } | exp { ... } | ID ';' <-- this rule { ... fprintf(stderr, "\n my id is '%s'", $1); ... if you check the output will get what I mean. I run my parser and I input the characters ab; to the program. According to my bison grammar this should be parsed as an ID followed by a ; . And at some extent it is what happens. However, when I try to use the $1 variable of the rule ID ';' the program outputs ab; to me instead of ab . running the program ab; <-- this my input

to solve the dangling else problem, I used the following solution: stmt : stmt_matched | stmt_unmatched ; stmt_unmatched : IF '(' exp ')' stmt | IF '(' exp ')' stmt_matched ELSE stmt_unmatched ; stmt_matched : IF '(' exp ')' stmt_matched ELSE stmt_matched | stmt_for | ... ; For defining the rules of grammar about the for loop, I produce a conflict shift/reduce due to the same problem: stmt_for : FOR '(' exp ';' exp ';' exp ')' stmt ; How can I solve this problem? Not all for statements are matched. Consider, for example if (c) for (;;) if (d) ; else ; So it is necessary to divide for

OK this is kind of an odd question because what I have here works the way I want it to. What I'm doing is writing a parser for a lambda calculus expression. So an expression can be one of four things: variable constant (expression expression) (lambda variable.expression) Now as you can see, the last two expressions have expressions within them. What I was trying to do was determine the overall expression so I can report which type it is. So for example the expression ((lambda x.(f1 x)) 100) is a combination overall. My idea was to return an END token from flex when it reached the end of file.

How can I handover an open file e.g. read by another scanner to the next scanner - and give it to the parser ? Flex buffers cannot easily be transferred from one scanner to another. Many details are private to the scanner and would need to be reverse-engineered, with the consequent loss of maintainability. However, it is not difficult to combine two (or more) scanner definitions into a single scanner, provided that the semantic types are compatible. It is simply necessary to give them different start conditions. Since the start condition can be set even outside of a scanner action, it is

I have the following problem while compiling the files. I have overwritten the definition of YYLTYPE as follows(though it is the same as default but I will extend it typedef struct YYLTYPE { int first_line; int first_column; int last_line; int last_column; } YYLTYPE; and when I add the following in the lex file I get the "yylloc undefined in this scope" error. #define YY_USER_INIT yylloc.first_line = yylloc.first_column = 1; Pastebin: flex file bison file makefile You need to put the definition of YYLTYPE and YYLTYPE_IS_DECLARED into a header file that you #include in both your .y and .l files

I am trying to compile QGIS in Visual Studio. I used OSGeo4W to download the packages, added Flex.exe and Bison.exe to my environment path. Downloaded QGIS Release 2.0, and launched a CMake-GUI with the option "Visual Studio 10". Then I configured my paths using the GUI tool. Then I hit configure and generate, and it worked. I looked in my directory and there were Visual Studio Solution files available for me. Then I hit "Build All" and I got the following output in the "Output Window" Generating flex_qgsexpressionlexer.cpp Generating qgsexpressionparser.cpp 1> C:\OSGeo4W\bin\bison.exe: cannot

I wrote bison code header: %{ #include "foo.h" %} And I defined a struct named 'Foo' in header. I'd like to use it as token type in Bison. %define api.value.type union %token <Foo*> bar Then I use -d option to generate bison.tab.h file. bison -d bison.y But there is no #include foo.h in bison.tab.h , and it use struct Foo to define the union YYSTYPE. //bison.tab.h union YYSTPE { Foo* bar; ... }; It caused error when compile this program: error: ‘Foo’ does not name a type Is there a way to include header file in bison.tab.h or another solution of this case? For includes that should appear in