Next: C++ Semantic Values, Previous: C++ Bison Interface, Up: C++ Parsers [Contents][Index]
The output files file.hh and file.cc declare
and define the parser class in the namespace yy
. The class name
defaults to parser
, but may be changed using ‘%define
parser_class_name {name}’. The interface of this class is detailed
below. It can be extended using the %parse-param
feature: its
semantics is slightly changed since it describes an additional member of the
parser class, and an additional argument for its constructor.
The types for semantic values. See C++ Semantic Values.
The type of locations, if location tracking is enabled. See C++ Location Values.
A structure that contains (only) the yytokentype
enumeration, which
defines the tokens. To refer to the token FOO
, use
yy::parser::token::FOO
. The scanner can use ‘typedef
yy::parser::token token;’ to “import” the token enumeration (see Calc++ Scanner).
This class derives from std::runtime_error
. Throw instances of it
from the scanner or from the actions to raise parse errors. This is
equivalent with first invoking error
to report the location and
message of the syntax error, and then to invoke YYERROR
to enter the
error-recovery mode. But contrary to YYERROR
which can only be
invoked from user actions (i.e., written in the action itself), the
exception can be thrown from functions invoked from the user action.
Build a new parser object. There are no arguments, unless ‘%parse-param {type1 arg1}’ was used.
Instantiate a syntax-error exception.
Run the syntactic analysis, and return 0 on success, 1 otherwise. Both
routines are equivalent, operator()
being more C++ish.
The whole function is wrapped in a try
/catch
block, so that
when an exception is thrown, the %destructor
s are called to release
the lookahead symbol, and the symbols pushed on the stack.
Exception related code in the generated parser is protected by CPP guards
(#if
) and disabled when exceptions are not supported (i.e., passing
-fno-exceptions
to the C++ compiler).
Get or set the stream used for tracing the parsing. It defaults to
std::cerr
.
Get or set the tracing level (an integral). Currently its value is either 0, no trace, or nonzero, full tracing.
The definition for this member function must be supplied by the user: the parser uses it to report a parser error occurring at l, described by m. If location tracking is not enabled, the second signature is used.
Next: C++ Semantic Values, Previous: C++ Bison Interface, Up: C++ Parsers [Contents][Index]