Reimplement pgbison and pgflex as perl scripts instead of bat files.

In the process, remove almost all knowledge of individual .y and .l files,
and instead get invocation settings from the relevant make files.
The exception is plpgsql's gram.y, which has a target with a different
name. It is hoped that this will make the scripts more future-proof,
so that they won't require adjustment every time we add a new .l or .y
file.

The logic is also notably less tortured than that forced on us
by the idiosyncrasies of the Windows command processor.

The .bat files are kept as thin wrappers for the perl scripts.

src/tools/msvc/pgbison.bat

 @echo off
-REM src/tools/msvc/pgbison.bat
-
-IF NOT EXIST src\tools\msvc\buildenv.pl goto nobuildenv
-perl -e "require 'src/tools/msvc/buildenv.pl'; while(($k,$v) = each %%ENV) { print qq[\@SET $k=$v\n]; }" > bldenv.bat
-CALL bldenv.bat
-del bldenv.bat
-:nobuildenv 
-
-SET BV=
-for /F "tokens=4 usebackq" %%f in (`bison -V`) do if "!BV!"=="" SET BV=%%f
-if "%BV%"=="" goto novarexp
-if %BV% EQU 1.875 goto bisonok
-if %BV% GEQ 2.2 goto bisonok
-goto nobison
-:bisonok
-
-if "%1" == "src\backend\parser\gram.y" call :generate %1 src\backend\parser\gram.c src\backend\parser\gram.h
-if "%1" == "src\backend\bootstrap\bootparse.y" call :generate %1 src\backend\bootstrap\bootparse.c
-if "%1" == "src\backend\replication\repl_gram.y" call :generate %1 src\backend\replication\repl_gram.c
-if "%1" == "src\pl\plpgsql\src\gram.y" call :generate %1 src\pl\plpgsql\src\pl_gram.c src\pl\plpgsql\src\pl_gram.h
-if "%1" == "src\test\isolation\specparse.y" call :generate %1 src\test\isolation\specparse.c
-if "%1" == "src\interfaces\ecpg\preproc\preproc.y" call :generate %1 src\interfaces\ecpg\preproc\preproc.c src\interfaces\ecpg\preproc\preproc.h
-if "%1" == "contrib\cube\cubeparse.y" call :generate %1 contrib\cube\cubeparse.c
-if "%1" == "contrib\seg\segparse.y" call :generate %1 contrib\seg\segparse.c
-
-echo Unknown bison input: %1
-exit 1
 
-:generate
-SET fn=%1
-SET cf=%2
-bison.exe -d %fn% -o %cf%
-if errorlevel 1 exit 1
-SET hf=%cf:~0,-2%.h
-if not "%hf%"=="%3" (
-        copy /y %hf% %3
-        if errorlevel 1 exit 1
-        del %hf%
-)
-exit 0
-
-
-:novarexp
-echo pgbison must be called with cmd /V:ON /C pgbison to work!
-exit 1
-
-:nobison
-echo WARNING! Bison install not found, or unsupported Bison version.
-echo Attempting to build without.
-exit 0
+REM src/tools/msvc/pgbison.bat
+REM all the logic for this now belongs in builddoc.pl. This file really
+REM only exists so you don't have to type "perl src/tools/msvc/pgbison.pl"
+REM Resist any temptation to add any logic here.
+@perl src/tools/msvc/pgbison.pl %*

src/tools/msvc/pgbison.pl

+# -*-perl-*- hey - emacs - this is a perl file
+
+# src/tools/msvc/pgbison.pl
+
+use strict;
+use File::Basename;
+
+# assume we are in the postgres source root
+
+require 'src/tools/msvc/buildenv.pl' if -e 'src/tools/msvc/buildenv.pl';
+
+my ($bisonver) = `bison -V`; # grab first line
+$bisonver=(split(/\s+/,$bisonver))[3]; # grab version number
+
+unless ($bisonver eq '1.875' || $bisonver ge '2.2')
+{
+    print "WARNING! Bison install not found, or unsupported Bison version.\n";
+    print "echo Attempting to build without.\n";
+    exit 0;
+}
+
+my $input = shift;
+if ($input !~ /\.y$/)
+{
+    print "Input must be a .y file\n";
+    exit 1;
+}
+elsif (!-e $input)
+{
+    print "Input file $input not found\n";
+    exit 1;
+}
+
+(my $output = $input) =~ s/\.y$/.c/;
+
+# plpgsql just has to be different
+$output =~ s/gram\.c$/pl_gram.c/ if $input =~ /src.pl.plpgsql.src.gram\.y$/;
+
+my $makefile = dirname($input) . "/Makefile";
+my ($mf, $make);
+open($mf,$makefile);
+local $/ = undef;
+$make=<$mf>;
+close($mf);
+my $headerflag = ($make =~ /\$\(BISON\)\s+-d/ ? '-d' : '');
+
+system("bison $headerflag $input -o $output");
+exit $? >> 8;

src/tools/msvc/pgflex.bat

 @echo off
-REM src/tools/msvc/pgflex.bat
-
-REM silence flex bleatings about file path style
-SET CYGWIN=nodosfilewarning
-
-IF NOT EXIST src\tools\msvc\buildenv.pl goto nobuildenv
-perl -e "require 'src/tools/msvc/buildenv.pl'; while(($k,$v) = each %%ENV) { print qq[\@SET $k=$v\n]; }" > bldenv.bat
-CALL bldenv.bat
-del bldenv.bat
-:nobuildenv 
-
-flex -V > NUL
-if errorlevel 1 goto noflex
 
-if "%1" == "src\backend\parser\scan.l" call :generate %1 src\backend\parser\scan.c -CF
-if "%1" == "src\backend\bootstrap\bootscanner.l" call :generate %1 src\backend\bootstrap\bootscanner.c
-if "%1" == "src\backend\utils\misc\guc-file.l" call :generate %1 src\backend\utils\misc\guc-file.c
-if "%1" == "src\backend\replication\repl_scanner.l" call :generate %1 src\backend\replication\repl_scanner.c
-if "%1" == "src\test\isolation\specscanner.l" call :generate %1 src\test\isolation\specscanner.c
-if "%1" == "src\interfaces\ecpg\preproc\pgc.l" call :generate %1 src\interfaces\ecpg\preproc\pgc.c
-if "%1" == "src\bin\psql\psqlscan.l" call :generate %1 src\bin\psql\psqlscan.c
-if "%1" == "contrib\cube\cubescan.l" call :generate %1 contrib\cube\cubescan.c
-if "%1" == "contrib\seg\segscan.l" call :generate %1 contrib\seg\segscan.c
-
-echo Unknown flex input: %1
-exit 1
-
-REM For non-reentrant scanners we need to fix up the yywrap macro definition
-REM to keep the MS compiler happy.
-REM For reentrant scanners (like the core scanner) we do not
-REM need to (and must not) change the yywrap definition.
-:generate
-flex %3 -o%2 %1
-if errorlevel 1 exit %errorlevel%
-perl -n -e "exit 1 if /^\%%option\s+reentrant/;" %1
-if errorlevel 1 exit 0
-perl -pi.bak -e "s/yywrap\(n\)/yywrap()/;" %2
-if errorlevel 1 exit %errorlevel%
-del %2.bak
-exit 0
-
-:noflex
-echo WARNING! flex install not found, attempting to build without
-exit 0
+REM src/tools/msvc/pgflex.bat
+REM all the logic for this now belongs in builddoc.pl. This file really
+REM only exists so you don't have to type "perl src/tools/msvc/pgflex.pl"
+REM Resist any temptation to add any logic here.
+@perl src/tools/msvc/pgflex.pl %*

src/tools/msvc/pgflex.pl

+# -*-perl-*- hey - emacs - this is a perl file
+
+# src/tools/msvc/pgflex.pl
+
+# silence flex bleatings about file path style
+$ENV{CYGWIN} = 'nodosfilewarning';
+
+use strict;
+use File::Basename;
+
+# assume we are in the postgres source root
+
+require 'src/tools/msvc/buildenv.pl' if -e 'src/tools/msvc/buildenv.pl';
+
+system('flex -V > NUL');
+if ($? != 0)
+{
+    print "WARNING! flex install not found, attempting to build without\n";
+    exit 0;
+}
+
+my $input = shift;
+if ($input !~ /\.l$/)
+{
+    print "Input must be a .l file\n";
+    exit 1;
+}
+elsif (!-e $input)
+{
+    print "Input file $input not found\n";
+    exit 1;
+}
+
+(my $output = $input) =~ s/\.l$/.c/;
+
+# get flex flags from make file
+my $makefile = dirname($input) . "/Makefile";
+my ($mf, $make);
+open($mf,$makefile);
+local $/ = undef;
+$make=<$mf>;
+close($mf);
+my $flexflags = ($make =~ /^\s*FLEXFLAGS\s*=\s*(\S.*)/m ? $1 : '');
+
+system("flex $flexflags -o$output $input");
+if ($? == 0)
+{
+
+    # For non-reentrant scanners we need to fix up the yywrap macro definition
+    # to keep the MS compiler happy.
+    # For reentrant scanners (like the core scanner) we do not
+    # need to (and must not) change the yywrap definition.
+    my $lfile;
+    open($lfile,$input) || die "opening $input for reading: $!";
+    my $lcode = <$lfile>;
+    close($lfile);
+    if ($lcode !~ /\%option\sreentrant/)
+    {
+        my $cfile;
+        open($cfile,$output) || die "opening $output for reading: $!";
+        my $ccode = <$cfile>;
+        close($cfile);
+        $ccode =~ s/yywrap\(n\)/yywrap()/;
+        open($cfile,">$output") || die "opening $output for reading: $!";
+        print $cfile $ccode;
+        close($cfile);
+    }
+
+    exit 0;
+
+}
+else
+{
+    exit $? >> 8;
+}
+