%@}
@end group
-%define api.value.type double
+%define api.value.type @{double@}
%token NUM
%% /* Grammar rules and actions follow. */
groupings (@pxref{Value Type, ,Data Types of Semantic Values}). The Bison
parser will use whatever type @code{api.value.type} is defined as; if you
don't define it, @code{int} is the default. Because we specify
-@code{double}, each token and each expression has an associated value, which
-is a floating point number. C code can use @code{YYSTYPE} to refer to the
-value @code{api.value.type}.
+@samp{@{double@}}, each token and each expression has an associated value,
+which is a floating point number. C code can use @code{YYSTYPE} to refer to
+the value @code{api.value.type}.
Each terminal symbol that is not a single-character literal must be
declared. (Single-character literals normally don't need to be declared.)
global variable @code{yylval}, which is where the Bison parser will look
for it. (The C data type of @code{yylval} is @code{YYSTYPE}, whose value
was defined at the beginning of the grammar via @samp{%define api.value.type
-double}; @pxref{Rpcalc Declarations,,Declarations for @code{rpcalc}}.)
+@{double@}}; @pxref{Rpcalc Declarations,,Declarations for @code{rpcalc}}.)
A token type code of zero is returned if the end-of-input is encountered.
(Bison recognizes any nonpositive value as indicating end-of-input.)
@group
/* Bison declarations. */
-%define api.value.type double
+%define api.value.type @{double@}
%token NUM
%left '-' '+'
%left '*' '/'
@code{api.value.type} like this:
@example
-%define api.value.type double
+%define api.value.type @{double@}
@end example
@noindent
or
@example
-%define api.value.type "struct semantic_type"
+%define api.value.type @{struct semantic_type@}
@end example
The value of @code{api.value.type} should be a type name that does not
If the @code{%define} variable @code{api.token.prefix} is defined
(@pxref{%define Summary,,api.token.prefix}), then it is also used to prefix
the union member names. For instance, with @samp{%define api.token.prefix
-TOK_}:
+@{TOK_@}}:
@example
/* For an "integer". */
return TOK_INT;
@end example
+This Bison extension cannot work if @code{%yacc} (or
+@option{-y}/@option{--yacc}) is enabled, as POSIX mandates that Yacc
+generate tokens as macros (e.g., @samp{#define INT 258}, or @samp{#define
+TOK_INT 258}).
+
This feature is new, and user feedback would be most welcome.
A similar feature is provided for C++ that in addition overcomes C++
@c ================================================== api.token.prefix
-@deffn Directive {%define api.token.prefix} @var{prefix}
+@deffn Directive {%define api.token.prefix} @{@var{prefix}@}
@itemize
@item Languages(s): all
@example
%token FILE for ERROR
-%define api.token.prefix "TOK_"
+%define api.token.prefix @{TOK_@}
%%
start: FILE for ERROR;
@end example
@item Default Value:
empty
@item History:
-introduced in Bison 2.8
+introduced in Bison 3.0
@end itemize
@end deffn
@c api.token.prefix
The line, starting at 1.
@end deftypeivar
-@deftypemethod {position} {uint} lines (int @var{height} = 1)
-Advance by @var{height} lines, resetting the column number.
+@deftypemethod {position} {void} lines (int @var{height} = 1)
+If @var{height} is not null, advance by @var{height} lines, resetting the
+column number. The resulting line number cannot be less than 1.
@end deftypemethod
@deftypeivar {position} {uint} column
The column, starting at 1.
@end deftypeivar
-@deftypemethod {position} {uint} columns (int @var{width} = 1)
-Advance by @var{width} columns, without changing the line number.
+@deftypemethod {position} {void} columns (int @var{width} = 1)
+Advance by @var{width} columns, without changing the line number. The
+resulting column number cannot be less than 1.
@end deftypemethod
@deftypemethod {position} {position&} operator+= (int @var{width})
The first, inclusive, position of the range, and the first beyond.
@end deftypeivar
-@deftypemethod {location} {uint} columns (int @var{width} = 1)
-@deftypemethodx {location} {uint} lines (int @var{height} = 1)
-Advance the @code{end} position.
+@deftypemethod {location} {void} columns (int @var{width} = 1)
+@deftypemethodx {location} {void} lines (int @var{height} = 1)
+Forwarded to the @code{end} position.
@end deftypemethod
@deftypemethod {location} {location} operator+ (const location& @var{end})
@deftypemethodx {location} {location} operator+ (int @var{width})
@deftypemethodx {location} {location} operator+= (int @var{width})
+@deftypemethodx {location} {location} operator- (int @var{width})
+@deftypemethodx {location} {location} operator-= (int @var{width})
Various forms of syntactic sugar.
@end deftypemethod
For instance, given the following declarations:
@example
-%define api.token.prefix "TOK_"
+%define api.token.prefix @{TOK_@}
%token <std::string> IDENTIFIER;
%token <int> INTEGER;
%token COLON;
@comment file: calc++-parser.yy
@example
-%define api.token.prefix "TOK_"
+%define api.token.prefix @{TOK_@}
%token
END 0 "end of file"
ASSIGN ":="
projects / bison.git / blobdiff