#
# Copyright (c) 1998-2007, PostgreSQL Global Development Group
#
-# $PostgreSQL: pgsql/src/interfaces/ecpg/preproc/Makefile,v 1.128 2007/08/22 08:20:58 meskes Exp $
+# $PostgreSQL: pgsql/src/interfaces/ecpg/preproc/Makefile,v 1.129 2007/10/26 14:17:53 tgl Exp $
#
#-------------------------------------------------------------------------
c_keywords.o keywords.o preproc.o parser.o: preproc.h
-parser.c: $(top_srcdir)/src/backend/parser/parser.c
- rm -f $@ && $(LN_S) $< .
-
distprep: $(srcdir)/preproc.c $(srcdir)/preproc.h $(srcdir)/pgc.c
install: all installdirs
rm -f '$(DESTDIR)$(bindir)/ecpg$(X)'
clean distclean:
- rm -f *.o ecpg$(X) parser.c
+ rm -f *.o ecpg$(X)
# garbage from partial builds
@rm -f y.tab.c y.tab.h
# garbage from development
--- /dev/null
+/*-------------------------------------------------------------------------
+ *
+ * parser.c
+ * Main entry point/driver for PostgreSQL grammar
+ *
+ * Note that the grammar is not allowed to perform any table access
+ * (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
+ * analyze.c and related files.
+ *
+ *
+ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * $PostgreSQL: pgsql/src/interfaces/ecpg/preproc/parser.c,v 1.1 2007/10/26 14:17:53 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres_fe.h"
+
+#include "extern.h"
+#include "preproc.h"
+
+
+static bool have_lookahead; /* is lookahead info valid? */
+static int lookahead_token; /* one-token lookahead */
+static YYSTYPE lookahead_yylval; /* yylval for lookahead token */
+static YYLTYPE lookahead_yylloc; /* yylloc for lookahead token */
+
+
+/*
+ * Intermediate filter between parser and base lexer (base_yylex in scan.l).
+ *
+ * The filter is needed because in some cases the standard SQL grammar
+ * requires more than one token lookahead. We reduce these cases to one-token
+ * lookahead by combining tokens here, in order to keep the grammar LALR(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. Furthermore it's not clear how to do it without re-introducing
+ * scanner backtrack, which would cost more performance than this filter
+ * layer does.
+ */
+int
+filtered_base_yylex(void)
+{
+ int cur_token;
+ int next_token;
+ YYSTYPE cur_yylval;
+ YYLTYPE cur_yylloc;
+
+ /* Get next token --- we might already have it */
+ if (have_lookahead)
+ {
+ cur_token = lookahead_token;
+ base_yylval = lookahead_yylval;
+ base_yylloc = lookahead_yylloc;
+ have_lookahead = false;
+ }
+ else
+ cur_token = base_yylex();
+
+ /* Do we need to look ahead for a possible multiword token? */
+ switch (cur_token)
+ {
+ case NULLS_P:
+ /*
+ * NULLS FIRST and NULLS LAST must be reduced to one token
+ */
+ cur_yylval = base_yylval;
+ cur_yylloc = base_yylloc;
+ next_token = base_yylex();
+ switch (next_token)
+ {
+ case FIRST_P:
+ cur_token = NULLS_FIRST;
+ break;
+ case LAST_P:
+ cur_token = NULLS_LAST;
+ break;
+ default:
+ /* save the lookahead token for next time */
+ lookahead_token = next_token;
+ lookahead_yylval = base_yylval;
+ lookahead_yylloc = base_yylloc;
+ have_lookahead = true;
+ /* and back up the output info to cur_token */
+ base_yylval = cur_yylval;
+ base_yylloc = cur_yylloc;
+ break;
+ }
+ break;
+
+ case WITH:
+ /*
+ * WITH CASCADED, LOCAL, or CHECK must be reduced to one token
+ *
+ * XXX an alternative way is to recognize just WITH_TIME and put
+ * the ugliness into the datetime datatype productions instead of
+ * WITH CHECK OPTION. However that requires promoting WITH to a
+ * fully reserved word. If we ever have to do that anyway
+ * (perhaps for SQL99 recursive queries), come back and simplify
+ * this code.
+ */
+ cur_yylval = base_yylval;
+ cur_yylloc = base_yylloc;
+ next_token = base_yylex();
+ switch (next_token)
+ {
+ case CASCADED:
+ cur_token = WITH_CASCADED;
+ break;
+ case LOCAL:
+ cur_token = WITH_LOCAL;
+ break;
+ case CHECK:
+ cur_token = WITH_CHECK;
+ break;
+ default:
+ /* save the lookahead token for next time */
+ lookahead_token = next_token;
+ lookahead_yylval = base_yylval;
+ lookahead_yylloc = base_yylloc;
+ have_lookahead = true;
+ /* and back up the output info to cur_token */
+ base_yylval = cur_yylval;
+ base_yylloc = cur_yylloc;
+ break;
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ return cur_token;
+}
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