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Diffstat (limited to 'doc/bison.texi')
| -rw-r--r-- | doc/bison.texi | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/doc/bison.texi b/doc/bison.texi index 77357813..2dab6c49 100644 --- a/doc/bison.texi +++ b/doc/bison.texi @@ -7546,15 +7546,18 @@ utility can be used without change as the definition of @code{yylex}. In addition to the user defined tokens, Bison generates a few special tokens that @code{yylex} may return. +@findex YYEOF The @code{YYEOF} token denotes the end of file, and signals to the parser that there is nothing left afterwards. @xref{Calling Convention}, for an example. +@findex YYUNDEF Returning @code{YYUNDEF} tells the parser that some lexical error was found. It will emit an error message about an ``invalid token'', and enter error-recovery (@pxref{Error Recovery}). Returning an unknown token kind results in the exact same behavior. +@findex YYerror Returning @code{YYerror} requires the parser to enter error-recovery @emph{without} emitting an error message. This way the lexical analyzer can produce an accurate error messages about the invalid input (something the |