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* src/output.c: Formatting changes.

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* src/machine.h: Remove, leaving its contents in...
* src/system.h: here.
Include stdio.h.
Adjust all dependencies on stdio.h and machine.h.
* src/getargs.h: New file.
Let all `extern' declarations about getargs.c be replaced with
inclusion of `getargs.h'.
* src/Makefile.am (noinst_HEADERS): Adjust.

* tests/calc.m4 (yyin): Be initialized in main, not on the global
scope.
(yyerror): Returns void, not int.
* doc/bison.texinfo: Formatting changes.
This commit is contained in:
Akim Demaille
2000-09-19 18:10:41 +00:00
parent 05a1d24b1e
commit ceed8467b7
31 changed files with 1409 additions and 1370 deletions
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@@ -1510,11 +1510,12 @@ real calculator, but it is adequate for the first example.
@subsection Running Bison to Make the Parser
@cindex running Bison (introduction)
Before running Bison to produce a parser, we need to decide how to arrange
all the source code in one or more source files. For such a simple example,
the easiest thing is to put everything in one file. The definitions of
@code{yylex}, @code{yyerror} and @code{main} go at the end, in the
``additional C code'' section of the file (@pxref{Grammar Layout, ,The Overall Layout of a Bison Grammar}).
Before running Bison to produce a parser, we need to decide how to
arrange all the source code in one or more source files. For such a
simple example, the easiest thing is to put everything in one file. The
definitions of @code{yylex}, @code{yyerror} and @code{main} go at the
end, in the ``additional C code'' section of the file (@pxref{Grammar
Layout, ,The Overall Layout of a Bison Grammar}).
For a large project, you would probably have several source files, and use
@code{make} to arrange to recompile them.
@@ -1628,8 +1629,8 @@ exp: NUM @{ $$ = $1; @}
@end example
@noindent
The functions @code{yylex}, @code{yyerror} and @code{main} can be the same
as before.
The functions @code{yylex}, @code{yyerror} and @code{main} can be the
same as before.
There are two important new features shown in this code.
@@ -1671,10 +1672,10 @@ Here is a sample run of @file{calc.y}:
Up to this point, this manual has not addressed the issue of @dfn{error
recovery}---how to continue parsing after the parser detects a syntax
error. All we have handled is error reporting with @code{yyerror}. Recall
that by default @code{yyparse} returns after calling @code{yyerror}. This
means that an erroneous input line causes the calculator program to exit.
Now we show how to rectify this deficiency.
error. All we have handled is error reporting with @code{yyerror}.
Recall that by default @code{yyparse} returns after calling
@code{yyerror}. This means that an erroneous input line causes the
calculator program to exit. Now we show how to rectify this deficiency.
The Bison language itself includes the reserved word @code{error}, which
may be included in the grammar rules. In the example below it has
@@ -1689,14 +1690,15 @@ line: '\n'
@end group
@end example
This addition to the grammar allows for simple error recovery in the event
of a parse error. If an expression that cannot be evaluated is read, the
error will be recognized by the third rule for @code{line}, and parsing
will continue. (The @code{yyerror} function is still called upon to print
its message as well.) The action executes the statement @code{yyerrok}, a
macro defined automatically by Bison; its meaning is that error recovery is
complete (@pxref{Error Recovery}). Note the difference between
@code{yyerrok} and @code{yyerror}; neither one is a misprint.@refill
This addition to the grammar allows for simple error recovery in the
event of a parse error. If an expression that cannot be evaluated is
read, the error will be recognized by the third rule for @code{line},
and parsing will continue. (The @code{yyerror} function is still called
upon to print its message as well.) The action executes the statement
@code{yyerrok}, a macro defined automatically by Bison; its meaning is
that error recovery is complete (@pxref{Error Recovery}). Note the
difference between @code{yyerrok} and @code{yyerror}; neither one is a
misprint.@refill
This form of error recovery deals with syntax errors. There are other
kinds of errors; for example, division by zero, which raises an exception
@@ -2186,12 +2188,13 @@ if it is the first thing in the file.
@cindex additional C code section
@cindex C code, section for additional
The @var{additional C code} section is copied verbatim to the end of
the parser file, just as the @var{C declarations} section is copied to
the beginning. This is the most convenient place to put anything
that you want to have in the parser file but which need not come before
the definition of @code{yyparse}. For example, the definitions of
@code{yylex} and @code{yyerror} often go here. @xref{Interface, ,Parser C-Language Interface}.
The @var{additional C code} section is copied verbatim to the end of the
parser file, just as the @var{C declarations} section is copied to the
beginning. This is the most convenient place to put anything that you
want to have in the parser file but which need not come before the
definition of @code{yyparse}. For example, the definitions of
@code{yylex} and @code{yyerror} often go here. @xref{Interface, ,Parser
C-Language Interface}.
If the last section is empty, you may omit the @samp{%%} that separates it
from the grammar rules.
@@ -3601,7 +3604,8 @@ with no arguments, as usual.
The Bison parser detects a @dfn{parse error} or @dfn{syntax error}
whenever it reads a token which cannot satisfy any syntax rule. An
action in the grammar can also explicitly proclaim an error, using the
macro @code{YYERROR} (@pxref{Action Features, ,Special Features for Use in Actions}).
macro @code{YYERROR} (@pxref{Action Features, ,Special Features for Use
in Actions}).
The Bison parser expects to report the error by calling an error
reporting function named @code{yyerror}, which you must supply. It is
@@ -3611,10 +3615,11 @@ receives one argument. For a parse error, the string is normally
@findex YYERROR_VERBOSE
If you define the macro @code{YYERROR_VERBOSE} in the Bison declarations
section (@pxref{Bison Declarations, ,The Bison Declarations Section}), then Bison provides a more verbose
and specific error message string instead of just plain @w{@code{"parse
error"}}. It doesn't matter what definition you use for
@code{YYERROR_VERBOSE}, just whether you define it.
section (@pxref{Bison Declarations, ,The Bison Declarations Section}),
then Bison provides a more verbose and specific error message string
instead of just plain @w{@code{"parse error"}}. It doesn't matter what
definition you use for @code{YYERROR_VERBOSE}, just whether you define
it.
The parser can detect one other kind of error: stack overflow. This
happens when the input contains constructions that are very deeply
@@ -5110,7 +5115,8 @@ token is reset to the token that originally caused the violation.
@item YYABORT
Macro to pretend that an unrecoverable syntax error has occurred, by
making @code{yyparse} return 1 immediately. The error reporting
function @code{yyerror} is not called. @xref{Parser Function, ,The Parser Function @code{yyparse}}.
function @code{yyerror} is not called. @xref{Parser Function, ,The
Parser Function @code{yyparse}}.
@item YYACCEPT
Macro to pretend that a complete utterance of the language has been