@} YYLTYPE;
@end example
-At the beginning of the parsing, Bison initializes all these fields to 1
-for @code{yylloc}.
+When @code{YYLTYPE} is not defined, at the beginning of the parsing, Bison
+initializes all these fields to 1 for @code{yylloc}. To initialize
+@code{yylloc} with a custom location type (or to chose a different
+initialization), use the @code{%initial-action} directive. @xref{Initial
+Action Decl, , Performing Actions before Parsing}.
@node Actions and Locations
@subsection Actions and Locations
parser (@pxref{Decl Summary,,%define api.push-pull}):
@example
-%define api.push-pull "push"
+%define api.push-pull push
@end example
In almost all cases, you want to ensure that your push parser is also
@example
%define api.pure
-%define api.push-pull "push"
+%define api.push-pull push
@end example
There is a major notable functional difference between the pure push parser
Bison also supports both the push parser interface along with the pull parser
interface in the same generated parser. In order to get this functionality,
-you should replace the @samp{%define api.push-pull "push"} declaration with the
-@samp{%define api.push-pull "both"} declaration. Doing this will create all of
+you should replace the @samp{%define api.push-pull push} declaration with the
+@samp{%define api.push-pull both} declaration. Doing this will create all of
the symbols mentioned earlier along with the two extra symbols, @code{yyparse}
and @code{yypull_parse}. @code{yyparse} can be used exactly as it normally
would be used. However, the user should note that it is implemented in the
generated parser by calling @code{yypull_parse}.
This makes the @code{yyparse} function that is generated with the
-@samp{%define api.push-pull "both"} declaration slower than the normal
+@samp{%define api.push-pull both} declaration slower than the normal
@code{yyparse} function. If the user
calls the @code{yypull_parse} function it will parse the rest of the input
stream. It is possible to @code{yypush_parse} tokens to select a subgrammar
@end example
Adding the @samp{%define api.pure} declaration does exactly the same thing to
-the generated parser with @samp{%define api.push-pull "both"} as it did for
-@samp{%define api.push-pull "push"}.
+the generated parser with @samp{%define api.push-pull both} as it did for
+@samp{%define api.push-pull push}.
@node Decl Summary
@subsection Bison Declaration Summary
@end deffn
@deffn {Directive} %define @var{variable}
+@deffnx {Directive} %define @var{variable} @var{value}
@deffnx {Directive} %define @var{variable} "@var{value}"
Define a variable to adjust Bison's behavior.
The possible choices for @var{variable}, as well as their meanings, depend on
Summary,,%language}, @pxref{Decl Summary,,%skeleton}).
It is an error if a @var{variable} is defined by @code{%define} multiple
-times, but @ref{Bison Options,,-D @var{name}[=@var{value}]}.
+times, but see @ref{Bison Options,,-D @var{name}[=@var{value}]}.
-Omitting @code{"@var{value}"} is always equivalent to specifying it as
+@var{value} must be placed in quotation marks if it contains any
+character other than a letter, underscore, period, dash, or non-initial
+digit.
+
+Omitting @code{"@var{value}"} entirely is always equivalent to specifying
@code{""}.
Some @var{variable}s may be used as Booleans.
of the following four conditions:
@enumerate
-@item @code{"@var{value}"} is @code{"true"}
+@item @code{@var{value}} is @code{true}
-@item @code{"@var{value}"} is omitted (or is @code{""}).
-This is equivalent to @code{"true"}.
+@item @code{@var{value}} is omitted (or @code{""} is specified).
+This is equivalent to @code{true}.
-@item @code{"@var{value}"} is @code{"false"}.
+@item @code{@var{value}} is @code{false}.
@item @var{variable} is never defined.
In this case, Bison selects a default value, which may depend on the selected
@item Accepted Values: Boolean
-@item Default Value: @code{"false"}
+@item Default Value: @code{false}
@end itemize
@c api.pure
(The current push parsing interface is experimental and may evolve.
More user feedback will help to stabilize it.)
-@item Accepted Values: @code{"pull"}, @code{"push"}, @code{"both"}
+@item Accepted Values: @code{pull}, @code{push}, @code{both}
-@item Default Value: @code{"pull"}
+@item Default Value: @code{pull}
@end itemize
@c api.push-pull
@c api.tokens.prefix
-@item error-verbose
-@findex %define error-verbose
-@itemize
-@item Languages(s):
-all.
-@item Purpose:
-Enable the generation of more verbose error messages than a instead of
-just plain @w{@code{"syntax error"}}. @xref{Error Reporting, ,The Error
-Reporting Function @code{yyerror}}.
-@item Accepted Values:
-Boolean
-@item Default Value:
-@code{false}
-@end itemize
-@c error-verbose
-
-
@item lr.default-reductions
@cindex default reductions
@findex %define lr.default-reductions
@item Accepted Values:
@itemize
-@item @code{"all"}.
+@item @code{all}.
For @acronym{LALR} and @acronym{IELR} parsers (@pxref{Decl
Summary,,lr.type}) by default, all states are permitted to contain
default reductions.
reductions in an @acronym{LALR} or @acronym{IELR} state can contain
tokens that are syntactically incorrect for some left contexts.
-@item @code{"consistent"}.
+@item @code{consistent}.
@cindex consistent states
A consistent state is a state that has only one possible action.
If that action is a reduction, then the parser does not need to request
soon as it @emph{needs} the syntactically unacceptable token from the
scanner.
-@item @code{"accepting"}.
+@item @code{accepting}.
@cindex accepting state
By default, the only default reduction permitted in a canonical
@acronym{LR} parser is the accept action in the accepting state, which
@item Default Value:
@itemize
-@item @code{"accepting"} if @code{lr.type} is @code{"canonical LR"}.
-@item @code{"all"} otherwise.
+@item @code{accepting} if @code{lr.type} is @code{canonical-lr}.
+@item @code{all} otherwise.
@end itemize
@end itemize
@item Accepted Values: Boolean
-@item Default Value: @code{"false"}
+@item Default Value: @code{false}
@item Caveats:
@item Accepted Values:
@itemize
-@item @code{"LALR"}.
+@item @code{lalr}.
While Bison generates @acronym{LALR} parser tables by default for
historical reasons, @acronym{IELR} or canonical @acronym{LR} is almost
always preferable for deterministic parsers.
from @acronym{IELR} and canonical @acronym{LR}.
@end itemize
-@item @code{"IELR"}.
+@item @code{ielr}.
@acronym{IELR} is a minimal @acronym{LR} algorithm.
That is, given any grammar (@acronym{LR} or non-@acronym{LR}),
@acronym{IELR} and canonical @acronym{LR} always accept exactly the same
of magnitude less as well.
This can significantly reduce the complexity of developing of a grammar.
-@item @code{"canonical LR"}.
+@item @code{canonical-lr}.
@cindex delayed syntax errors
@cindex syntax errors delayed
The only advantage of canonical @acronym{LR} over @acronym{IELR} is
facilitate the development of a grammar.
@end itemize
-@item Default Value: @code{"LALR"}
+@item Default Value: @code{lalr}
@end itemize
Obsoleted by @code{api.namespace}
@c namespace
+
+@c ================================================== parse.assert
@item parse.assert
@findex %define parse.assert
@end itemize
@c parse.assert
+
+@c ================================================== parse.error
+@item parse.error
+@findex %define parse.error
+@itemize
+@item Languages(s):
+all.
+@item Purpose:
+Control the kind of error messages passed to the error reporting
+function. @xref{Error Reporting, ,The Error Reporting Function
+@code{yyerror}}.
+@item Accepted Values:
+@itemize
+@item @code{simple}
+Error messages passed to @code{yyerror} are simply @w{@code{"syntax
+error"}}.
+@item @code{verbose}
+Error messages report the unexpected token, and possibly the expected
+ones.
+@end itemize
+
+@item Default Value:
+@code{simple}
+@end itemize
+@c parse.error
+
+
+@c ================================================== parse.trace
@item parse.trace
@findex %define parse.trace
More user feedback will help to stabilize it.)
You call the function @code{yypush_parse} to parse a single token. This
-function is available if either the @samp{%define api.push-pull "push"} or
-@samp{%define api.push-pull "both"} declaration is used.
+function is available if either the @samp{%define api.push-pull push} or
+@samp{%define api.push-pull both} declaration is used.
@xref{Push Decl, ,A Push Parser}.
@deftypefun int yypush_parse (yypstate *yyps)
More user feedback will help to stabilize it.)
You call the function @code{yypull_parse} to parse the rest of the input
-stream. This function is available if the @samp{%define api.push-pull "both"}
+stream. This function is available if the @samp{%define api.push-pull both}
declaration is used.
@xref{Push Decl, ,A Push Parser}.
More user feedback will help to stabilize it.)
You call the function @code{yypstate_new} to create a new parser instance.
-This function is available if either the @samp{%define api.push-pull "push"} or
-@samp{%define api.push-pull "both"} declaration is used.
+This function is available if either the @samp{%define api.push-pull push} or
+@samp{%define api.push-pull both} declaration is used.
@xref{Push Decl, ,A Push Parser}.
@deftypefun yypstate *yypstate_new (void)
More user feedback will help to stabilize it.)
You call the function @code{yypstate_delete} to delete a parser instance.
-function is available if either the @samp{%define api.push-pull "push"} or
-@samp{%define api.push-pull "both"} declaration is used.
+function is available if either the @samp{%define api.push-pull push} or
+@samp{%define api.push-pull both} declaration is used.
@xref{Push Decl, ,A Push Parser}.
@deftypefun void yypstate_delete (yypstate *yyps)
@cindex parse error
@cindex syntax error
-The Bison parser detects a @dfn{syntax error} or @dfn{parse error}
+The Bison parser detects a @dfn{syntax error} (or @dfn{parse 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
receives one argument. For a syntax error, the string is normally
@w{@code{"syntax error"}}.
-@findex %define error-verbose
-If you invoke the directive @samp{%define error-verbose} in the Bison
+@findex %define parse.error
+If you invoke @samp{%define parse.error 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{"syntax error"}}.
@item -D @var{name}[=@var{value}]
@itemx --define=@var{name}[=@var{value}]
-@item -F @var{name}[=@var{value}]
+@itemx -F @var{name}[=@var{value}]
@itemx --force-define=@var{name}[=@var{value}]
Each of these is equivalent to @samp{%define @var{name} "@var{value}"}
(@pxref{Decl Summary, ,%define}) except that Bison processes multiple
@comment file: calc++-parser.yy
@example
%define parse.trace
-%define error-verbose
+%define parse.error verbose
@end example
@noindent
a range composed of a pair of positions (possibly spanning several
files). The location class is an inner class of the parser; the name
is @code{Location} by default, and may also be renamed using
-@samp{%define location_type "@var{class-name}}.
+@samp{%define location_type "@var{class-name}"}.
The location class treats the position as a completely opaque value.
By default, the class name is @code{Position}, but this can be changed
@deftypemethod {YYParser} {boolean} getErrorVerbose ()
@deftypemethodx {YYParser} {void} setErrorVerbose (boolean @var{verbose})
Get or set the option to produce verbose error messages. These are only
-available with the @samp{%define error-verbose} directive, which also turn on
+available with @samp{%define parse.error verbose}, which also turns on
verbose error messages.
@end deftypemethod
@deffn {Directive} %define @var{define-variable}
@deffnx {Directive} %define @var{define-variable} @var{value}
+@deffnx {Directive} %define @var{define-variable} "@var{value}"
Define a variable to adjust Bison's behavior.
@xref{Decl Summary,,%define}.
@end deffn
@end deffn
@deffn {Directive} %error-verbose
-An obsolete directive standing for @samp{%define error-verbose}.
+An obsolete directive standing for @samp{%define parse.error verbose}.
@end deffn
@deffn {Directive} %file-prefix "@var{prefix}"
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 @samp{%define error-verbose} is preferred (@pxref{Error
-Reporting, ,The Error Reporting Function @code{yyerror}}).
+it. Using @samp{%define parse.error verbose} is preferred
+(@pxref{Error Reporting, ,The Error Reporting Function @code{yyerror}}).
@end deffn
@deffn {Macro} YYINITDEPTH
@bye
+@c Local Variables:
+@c fill-column: 76
+@c End:
+
@c LocalWords: texinfo setfilename settitle setchapternewpage finalout
@c LocalWords: ifinfo smallbook shorttitlepage titlepage GPL FIXME iftex
@c LocalWords: akim fn cp syncodeindex vr tp synindex dircategory direntry
projects / bison.git / blobdiff