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/*-------------------------------------------------------------------------
*
* parser.c
* Main entry point/driver for PostgreSQL parser
*
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/parser/parser.c,v 1.46 2000/09/12 21:07:02 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "nodes/parsenodes.h"
#include "nodes/pg_list.h"
#include "parser/analyze.h"
#include "parser/gramparse.h"
#include "parser/parse.h"
#include "parser/parser.h"
#include "parser/parse_expr.h"
#if defined(FLEX_SCANNER)
extern void DeleteBuffer(void);
#endif /* FLEX_SCANNER */
char *parseString; /* the char* which holds the string to be
* parsed */
List *parsetree; /* result of parsing is left here */
static int lookahead_token; /* one-token lookahead */
static bool have_lookahead; /* lookahead_token set? */
#ifdef SETS_FIXED
static void fixupsets();
static void define_sets();
#endif
/*
* parser-- returns a list of parse trees
*/
List *
parser(char *str, Oid *typev, int nargs)
{
List *queryList;
int yyresult;
parseString = str;
parsetree = NIL; /* in case parser forgets to set it */
have_lookahead = false;
scanner_init();
parser_init(typev, nargs);
parse_expr_init();
yyresult = yyparse();
#if defined(FLEX_SCANNER)
DeleteBuffer();
#endif /* FLEX_SCANNER */
clearerr(stdin);
if (yyresult) /* error */
return (List *) NULL;
queryList = parse_analyze(parsetree, NULL);
#ifdef SETS_FIXED
/*
* Fixing up sets calls the parser, so it reassigns the global
* variable parsetree. So save the real parsetree.
*/
savetree = parsetree;
foreach(parse, savetree)
{ /* savetree is really a list of parses */
/* find set definitions embedded in query */
fixupsets((Query *) lfirst(parse));
}
return savetree;
#endif
return queryList;
}
/*
* 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;
}
#ifdef SETS_FIXED
static void
fixupsets(Query *parse)
{
if (parse == NULL)
return;
if (parse->commandType == CMD_UTILITY) /* utility */
return;
if (parse->commandType != CMD_INSERT)
return;
define_sets(parse);
}
/* Recursively find all of the Consts in the parsetree. Some of
* these may represent a set. The value of the Const will be the
* query (a string) which defines the set. Call SetDefine to define
* the set, and store the OID of the new set in the Const instead.
*/
static void
define_sets(Node *clause)
{
Oid setoid;
Type t = typeidType(OIDOID);
Oid typeoid = typeTypeId(t);
Size oidsize = typeLen(t);
bool oidbyval = typeByVal(t);
if (clause == NULL)
return;
else if (IsA(clause, LispList))
{
define_sets(lfirst(clause));
define_sets(lnext(clause));
}
else if (IsA(clause, Const))
{
if (get_constisnull((Const) clause) ||
!get_constisset((Const) clause))
return;
setoid = SetDefine(((Const *) clause)->constvalue,
typeidTypeName(((Const *) clause)->consttype));
set_constvalue((Const) clause, setoid);
set_consttype((Const) clause, typeoid);
set_constlen((Const) clause, oidsize);
set_constypeByVal((Const) clause, oidbyval);
}
else if (IsA(clause, Iter))
define_sets(((Iter *) clause)->iterexpr);
else if (single_node(clause))
return;
else if (or_clause(clause) || and_clause(clause))
{
List *temp;
/* mapcan */
foreach(temp, ((Expr *) clause)->args)
define_sets(lfirst(temp));
}
else if (is_funcclause(clause))
{
List *temp;
/* mapcan */
foreach(temp, ((Expr *) clause)->args)
define_sets(lfirst(temp));
}
else if (IsA(clause, ArrayRef))
define_sets(((ArrayRef *) clause)->refassgnexpr);
else if (not_clause(clause))
define_sets(get_notclausearg(clause));
else if (is_opclause(clause))
{
define_sets(get_leftop(clause));
define_sets(get_rightop(clause));
}
}
#endif
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