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 The Lexical Analyzer Function `yylex'
 =====================================
 
    The "lexical analyzer" function, `yylex', recognizes tokens from the
 input stream and returns them to the parser.  Bison does not create
 this function automatically; you must write it so that `yyparse' can
 call it.  The function is sometimes referred to as a lexical scanner.
 
    In simple programs, `yylex' is often defined at the end of the Bison
 grammar file.  If `yylex' is defined in a separate source file, you
 need to arrange for the token-type macro definitions to be available
 there.  To do this, use the `-d' option when you run Bison, so that it
 will write these macro definitions into a separate header file
 `NAME.tab.h' which you can include in the other source files that need
 it.   Invoking Bison Invocation.
 

Menu

 
* Calling Convention  How `yyparse' calls `yylex'.
* Token Values      How `yylex' must return the semantic value
                         of the token it has read.
* Token Positions   How `yylex' must return the text position
                         (line number, etc.) of the token, if the
                         actions want that.
* Pure Calling      How the calling convention differs
                         in a pure parser ( A Pure (Reentrant) Parser Pure Decl.).
 

Info Catalog

(bison.info) Parser Function

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(bison.info) Error Reporting