diff --git a/src/tools/msvc/pgbison.bat b/src/tools/msvc/pgbison.bat
index c5d355e5ab..27b5353a55 100755
--- a/src/tools/msvc/pgbison.bat
+++ b/src/tools/msvc/pgbison.bat
@@ -1,51 +1,7 @@
 @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 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 %*
diff --git a/src/tools/msvc/pgbison.pl b/src/tools/msvc/pgbison.pl
new file mode 100644
index 0000000000..c48863aff6
--- /dev/null
+++ b/src/tools/msvc/pgbison.pl
@@ -0,0 +1,48 @@
+# -*-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 $? >> 8;
diff --git a/src/tools/msvc/pgflex.bat b/src/tools/msvc/pgflex.bat
index e26724cc5f..144422d313 100755
--- a/src/tools/msvc/pgflex.bat
+++ b/src/tools/msvc/pgflex.bat
@@ -1,45 +1,7 @@
 @echo off
+
 REM src/tools/msvc/pgflex.bat
-
-REM silence flex bleatings about file path style
-SET CYGWIN=nodosfilewarning
-
-IF NOT EXIST src\tools\msvc\buildenv.pl goto nobuildenv
-perl -e "require 'src/tools/msvc/buildenv.pl'; while(($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 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 %*
diff --git a/src/tools/msvc/pgflex.pl b/src/tools/msvc/pgflex.pl
new file mode 100644
index 0000000000..332d422f64
--- /dev/null
+++ b/src/tools/msvc/pgflex.pl
@@ -0,0 +1,76 @@
+# -*-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;
+}
+