@ -7,32 +7,26 @@
* ( since we need to be able to do basic parsing even while inside an
* aborted transaction ) . Therefore , the data structures returned by
* the grammar are " raw " parsetrees that still need to be analyzed by
* parse_analyze .
* analyze . c and related files .
*
*
* Portions Copyright ( c ) 1996 - 2006 , PostgreSQL Global Development Group
* Portions Copyright ( c ) 1994 , Regents of the University of California
*
* IDENTIFICATION
* $ PostgreSQL : pgsql / src / backend / parser / parser . c , v 1.64 2006 / 03 / 05 15 : 58 : 34 momjian Exp $
* $ PostgreSQL : pgsql / src / backend / parser / parser . c , v 1.65 2006 / 03 / 07 01 : 00 : 17 tgl Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
# include "postgres.h"
# include "nodes/parsenodes.h"
# include "parser/gramparse.h"
# include "parser/parse.h"
# include "parser/parser.h"
# include "parser/parse_expr.h"
List * parsetree ; /* result of parsing is left here */
static int lookahead_token ; /* one-token lookahead */
static bool have_lookahead ; /* lookahead_token set? */
/*
* raw_parser
@ -46,12 +40,11 @@ raw_parser(const char *str)
int yyresult ;
parsetree = NIL ; /* in case grammar forgets to set it */
have_lookahead = false ;
scanner_init ( str ) ;
parser_init ( ) ;
yyresult = yyparse ( ) ;
yyresult = base_ yyparse( ) ;
scanner_finish ( ) ;
@ -60,48 +53,3 @@ raw_parser(const char *str)
return parsetree ;
}
/*
* Intermediate filter between parser and base lexer ( base_yylex in scan . l ) .
*
* The filter is needed because in some cases SQL92 requires more than one
* token lookahead . We reduce these cases to one - token lookahead by combining
* tokens here , in order to keep the grammar LR ( 1 ) .
*
* Using a filter is simpler than trying to recognize multiword tokens
* directly in scan . l , because we ' d have to allow for comments between the
* words . . .
*/
int
yylex ( void )
{
int cur_token ;
/* Get next token --- we might already have it */
if ( have_lookahead )
{
cur_token = lookahead_token ;
have_lookahead = false ;
}
else
cur_token = base_yylex ( ) ;
/* Do we need to look ahead for a possible multiword token? */
switch ( cur_token )
{
case UNION :
/* UNION JOIN must be reduced to a single UNIONJOIN token */
lookahead_token = base_yylex ( ) ;
if ( lookahead_token = = JOIN )
cur_token = UNIONJOIN ;
else
have_lookahead = true ;
break ;
default :
break ;
}
return cur_token ;
}
Tom Lane
20 years ago