* Copying This Manual:: License for copying this manual.
* Index:: Cross-references to the text.
-@detailmenu --- The Detailed Node Listing ---
+@detailmenu
+ --- The Detailed Node Listing ---
The Concepts of Bison
a semantic value (the value of an integer,
the name of an identifier, etc.).
* Semantic Actions:: Each rule can have an action containing C code.
+* GLR Parsers:: Writing parsers for general context-free languages
+* Locations Overview:: Tracking Locations.
* Bison Parser:: What are Bison's input and output,
how is the output used?
* Stages:: Stages in writing and running Bison grammars.
Operator precedence is introduced.
* Simple Error Recovery:: Continuing after syntax errors.
* Location Tracking Calc:: Demonstrating the use of @@@var{n} and @@$.
-* Multi-function Calc:: Calculator with memory and trig functions.
- It uses multiple data-types for semantic values.
+* Multi-function Calc:: Calculator with memory and trig functions.
+ It uses multiple data-types for semantic values.
* Exercises:: Ideas for improving the multi-function calculator.
Reverse Polish Notation Calculator
* Rules:: How to write grammar rules.
* Recursion:: Writing recursive rules.
* Semantics:: Semantic values and actions.
+* Locations:: Locations and actions.
* Declarations:: All kinds of Bison declarations are described here.
* Multiple Parsers:: Putting more than one Bison parser in one program.
Outline of a Bison Grammar
-* Prologue:: Syntax and usage of the prologue (declarations section).
+* Prologue:: Syntax and usage of the prologue.
* Bison Declarations:: Syntax and usage of the Bison declarations section.
* Grammar Rules:: Syntax and usage of the grammar rules section.
-* Epilogue:: Syntax and usage of the epilogue (additional code section).
+* Epilogue:: Syntax and usage of the epilogue.
Defining Language Semantics
This says when, why and how to use the exceptional
action in the middle of a rule.
+Tracking Locations
+
+* Location Type:: Specifying a data type for locations.
+* Actions and Locations:: Using locations in actions.
+* Location Default Action:: Defining a general way to compute locations.
+
Bison Declarations
* Token Decl:: Declaring terminal symbols.
of the token it has read.
* Token Positions:: How @code{yylex} must return the text position
(line number, etc.) of the token, if the
- actions want that.
+ actions want that.
* Pure Calling:: How the calling convention differs
in a pure parser (@pxref{Pure Decl, ,A Pure (Reentrant) Parser}).
* Tie-in Recovery:: Lexical tie-ins have implications for how
error recovery rules must be written.
-Understanding or Debugging Your Parser
+Debugging Your Parser
* Understanding:: Understanding the structure of your parser.
* Tracing:: Tracing the execution of your parser.
* Bison Options:: All the options described in detail,
in alphabetical order by short options.
* Option Cross Key:: Alphabetical list of long options.
+* Yacc Library:: Yacc-compatible @code{yylex} and @code{main}.
Frequently Asked Questions
If @samp{%parse-param @{int *nastiness@}} is used, then:
@example
-void yyerror (int *randomness, char const *msg); /* Yacc parsers. */
-void yyerror (int *randomness, char const *msg); /* GLR parsers. */
+void yyerror (int *nastiness, char const *msg); /* Yacc parsers. */
+void yyerror (int *nastiness, char const *msg); /* GLR parsers. */
@end example
Finally, GLR and Yacc parsers share the same @code{yyerror} calling
@noindent
will produce @file{output.c++} and @file{outfile.h++}.
+For compatibility with @acronym{POSIX}, the standard Bison
+distribution also contains a shell script called @command{yacc} that
+invokes Bison with the @option{-y} option.
+
@menu
* Bison Options:: All the options described in detail,
in alphabetical order by short options.
* Option Cross Key:: Alphabetical list of long options.
+* Yacc Library:: Yacc-compatible @code{yylex} and @code{main}.
@end menu
@node Bison Options
@file{y.tab.c}, and the other outputs are called @file{y.output} and
@file{y.tab.h}. The purpose of this option is to imitate Yacc's output
file name conventions. Thus, the following shell script can substitute
-for Yacc:
+for Yacc, and the Bison distribution contains such a script for
+compatibility with @acronym{POSIX}:
@example
-bison -y $*
+#! /bin/sh
+bison -y "$@"
@end example
@end table
@end example
@end ifinfo
+@node Yacc Library
+@section Yacc Library
+
+The Yacc library contains default implementations of the
+@code{yyerror} and @code{main} functions. These default
+implementations are normally not useful, but @acronym{POSIX} requires
+them. To use the Yacc library, link your program with the
+@option{-ly} option. Note that Bison's implementation of the Yacc
+library is distributed under the terms of the @acronym{GNU} General
+Public License (@pxref{Copying}).
+
+If you use the Yacc library's @code{yyerror} function, you should
+declare @code{yyerror} as follows:
+
+@example
+int yyerror (char const *);
+@end example
+
+Bison ignores the @code{int} value returned by this @code{yyerror}.
+If you use the Yacc library's @code{main} function, your
+@code{yyparse} function should have the following type signature:
+
+@example
+int yyparse (void);
+@end example
+
@c ================================================= Invoking Bison
@node FAQ
@end deffn
@deffn {Macro} YYERROR_VERBOSE
-An obsolete macro that you define with @code{#define} in the Bison
-declarations section to request verbose, specific error message strings
+An obsolete macro that you define with @code{#define} in the prologue
+to request verbose, specific error message strings
when @code{yyerror} is called. It doesn't matter what definition you
use for @code{YYERROR_VERBOSE}, just whether you define it. Using
@code{%error-verbose} is preferred.
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