Minor improvements for reformat_dat_file.pl.

Use Getopt::Long in preference to hand-rolled option parsing code.

Also, remove "-I .../backend/catalog" switch from the Makefile
invocations.  That's been unnecessary for some time, and leaving it
there gives the false impression it's needed in manual invocations.

John Naylor (extracted from a larger but more controversial patch)

Discussion: https://postgr.es/m/CACPNZCsHdcQN2jQ1=ptbi1Co2Nj3aHgRCUMk62=ThgWNabPY+Q@mail.gmail.com

src/include/catalog/Makefile

@@ -13,19 +13,16 @@ subdir = src/include/catalog
 top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
-# location of Catalog.pm
-catalogdir = $(top_srcdir)/src/backend/catalog
-
 # 'make reformat-dat-files' is a convenience target for rewriting the
 # catalog data files in our standard format.  This includes collapsing
 # out any entries that are redundant with a BKI_DEFAULT annotation.
 reformat-dat-files:
-	$(PERL) -I $(catalogdir) $(srcdir)/reformat_dat_file.pl -o $(srcdir) $(srcdir)/pg_*.dat
+	$(PERL) $(srcdir)/reformat_dat_file.pl --output $(srcdir) $(srcdir)/pg_*.dat
 
 # 'make expand-dat-files' is a convenience target for expanding out all
 # default values in the catalog data files.  This should be run before
 # altering or removing any BKI_DEFAULT annotation.
 expand-dat-files:
-	$(PERL) -I $(catalogdir) $(srcdir)/reformat_dat_file.pl -o $(srcdir) $(srcdir)/pg_*.dat --full-tuples
+	$(PERL) $(srcdir)/reformat_dat_file.pl --output $(srcdir) $(srcdir)/pg_*.dat --full-tuples
 
 .PHONY: reformat-dat-files expand-dat-files

src/include/catalog/reformat_dat_file.pl

@@ -20,9 +20,11 @@
 use strict;
 use warnings;
 
+use FindBin;
+use Getopt::Long;
+
 # If you copy this script to somewhere other than src/include/catalog,
 # you'll need to modify this "use lib" or provide a suitable -I switch.
-use FindBin;
 use lib "$FindBin::RealBin/../../backend/catalog/";
 use Catalog;
 
@@ -34,35 +36,16 @@ use Catalog;
 my @METADATA =
   ('oid', 'oid_symbol', 'array_type_oid', 'descr', 'autogenerated');
 
-my @input_files;
+# Process command line switches.
 my $output_path = '';
 my $full_tuples = 0;
 
-# Process command line switches.
-while (@ARGV)
-{
-	my $arg = shift @ARGV;
-	if ($arg !~ /^-/)
-	{
-		push @input_files, $arg;
-	}
-	elsif ($arg =~ /^-o/)
-	{
-		$output_path = length($arg) > 2 ? substr($arg, 2) : shift @ARGV;
-	}
-	elsif ($arg eq '--full-tuples')
-	{
-		$full_tuples = 1;
-	}
-	else
-	{
-		usage();
-	}
-}
+GetOptions(
+	'output=s'    => \$output_path,
+	'full-tuples' => \$full_tuples) || usage();
 
 # Sanity check arguments.
-die "No input files.\n"
-  if !@input_files;
+die "No input files.\n" unless @ARGV;
 
 # Make sure output_path ends in a slash.
 if ($output_path ne '' && substr($output_path, -1) ne '/')
@@ -76,7 +59,7 @@ if ($output_path ne '' && substr($output_path, -1) ne '/')
 my %catalogs;
 my %catalog_data;
 my @catnames;
-foreach my $datfile (@input_files)
+foreach my $datfile (@ARGV)
 {
 	$datfile =~ /(.+)\.dat$/
 	  or die "Input files need to be data (.dat) files.\n";
@@ -130,7 +113,7 @@ foreach my $catname (@catnames)
 		  if !(grep { $_ eq $attname } @METADATA);
 	}
 
-	# Overwrite .dat files in place, since they are under version control.
+	# Write output files to specified directory.
 	my $datfile = "$output_path$catname.dat";
 	open my $dat, '>', $datfile
 	  or die "can't open $datfile: $!";
@@ -318,10 +301,12 @@ sub usage
 Usage: reformat_dat_file.pl [options] datafile...
 
 Options:
-    -o PATH          write output files to PATH instead of current directory
+    --output PATH    output directory (default '.')
     --full-tuples    write out full tuples, including default values
 
-Expects a list of .dat files as arguments.
+Non-option arguments are the names of input .dat files.
+Updated files are written to the output directory,
+possibly overwriting the input files.
 
 EOM
 }