Re-implement psql's input scanning to use a flex-generated lexer, as per

recent discussion.  The lexer is used for both SQL command text and
backslash commands.  The purpose of this change is to make it easier to
track the behavior of the backend's SQL lexer --- essentially identical
flex rules are now used by psql.  Also, this cleans up a lot of very
squirrelly code in mainloop.c and command.c.  The flex code is somewhat
bulkier than the removed code, but should be lots easier to maintain.

Author: tglsfdc

src/bin/psql/.cvsignore

@@ -1 +1,2 @@
+psqlscan.c
 sql_help.h

src/bin/psql/Makefile

@@ -5,7 +5,7 @@
 # Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
 # Portions Copyright (c) 1994, Regents of the University of California
 #
-# $PostgreSQL: pgsql/src/bin/psql/Makefile,v 1.38 2003/11/29 19:52:06 pgsql Exp $
+# $PostgreSQL: pgsql/src/bin/psql/Makefile,v 1.39 2004/02/19 19:40:08 tgl Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -19,7 +19,10 @@ override CPPFLAGS := -I$(libpq_srcdir) $(CPPFLAGS) -DFRONTEND
 
 OBJS=	command.o common.o help.o input.o stringutils.o mainloop.o copy.o \
 	startup.o prompt.o variables.o large_obj.o print.o describe.o \
-	tab-complete.o mbprint.o
+	psqlscan.o tab-complete.o mbprint.o
+
+FLEXFLAGS = -Cfe
+
 
 all: submake-libpq submake-libpgport psql
 
@@ -36,6 +39,13 @@ $(srcdir)/sql_help.h:
 	@echo "*** Perl is needed to build psql help."
 endif
 
+$(srcdir)/psqlscan.c: psqlscan.l
+ifdef FLEX
+	$(FLEX) $(FLEXFLAGS) -o'$@' $<
+else
+	@$(missing) flex $< $@
+endif
+
 distprep: $(srcdir)/sql_help.h
 
 install: all installdirs
@@ -47,8 +57,9 @@ installdirs:
 uninstall:
 	rm -f $(DESTDIR)$(bindir)/psql$(X)
 
+# psqlscan.c is in the distribution tarball, so is not cleaned here
 clean distclean:
 	rm -f psql$(X) $(OBJS)
 
 maintainer-clean: distclean
-	rm -f $(srcdir)/sql_help.h
+	rm -f $(srcdir)/sql_help.h $(srcdir)/psqlscan.c