The Parser Function `yyparse'
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You call the function `yyparse' to cause parsing to occur. This
function reads tokens, executes actions, and ultimately returns when it
encounters end-of-input or an unrecoverable syntax error. You can also
write an action which directs `yyparse' to return immediately without
reading further.
The value returned by `yyparse' is 0 if parsing was successful
(return is due to end-of-input).
The value is 1 if parsing failed (return is due to a syntax error).
In an action, you can cause immediate return from `yyparse' by using
these macros:
`YYACCEPT'
Return immediately with value 0 (to report success).
`YYABORT'
Return immediately with value 1 (to report failure).