The parsing actions of error and accept can be simulated in an action by use of macros YYACCEPT
and YYERROR
. The YYACCEPT
macro causes yyparse() to return the value 0; YYERROR
causes the parser to behave as if the current input symbol had been a syntax error; yyerror() is called, and error recovery takes place.
These mechanisms can be used to simulate parsers with multiple end-markers or context-sensitive syntax checking.