generate-cmdlist: re-implement as shell script

527ec39 (generate-cmdlist: parse common group commands, 2015-05-21)
replaced generate-cmdlist.sh with a more functional Perl version,
generate-cmdlist.perl. The Perl version gleans named tags from a new
"common groups" section in command-list.txt and recognizes those
tags in "command list" section entries in place of the old 'common'
tag. This allows git-help to, not only recognize, but also group
common commands.

Although the tests require Perl, 527ec39 creates an unconditional
dependence upon Perl in the build system itself, which can not be
overridden with NO_PERL. Such a dependency may be undesirable; for
instance, the 'git-lite' package in the FreeBSD ports tree is
intended as a minimal Git installation (which may, for example, be
useful on servers needing only local clone and update capability),
which, historically, has not depended upon Perl[1].

Therefore, revive generate-cmdlist.sh and extend it to recognize
"common groups" and its named tags. Retire generate-cmdlist.perl.

[1]: http://thread.gmane.org/gmane.comp.version-control.git/275905/focus=276132

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -1687,10 +1687,10 @@ $(BUILT_INS): git$X
 	ln -s $< $@ 2>/dev/null || \
 	cp $< $@
 
-common-cmds.h: generate-cmdlist.perl command-list.txt
+common-cmds.h: generate-cmdlist.sh command-list.txt
 
 common-cmds.h: $(wildcard Documentation/git-*.txt)
-	$(QUIET_GEN)$(PERL_PATH) generate-cmdlist.perl command-list.txt > $@+ && mv $@+ $@
+	$(QUIET_GEN)./generate-cmdlist.sh command-list.txt >$@+ && mv $@+ $@
 
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
 	$(localedir_SQ):$(NO_CURL):$(USE_GETTEXT_SCHEME):$(SANE_TOOL_PATH_SQ):\

generate-cmdlist.perl

@@ -1,50 +0,0 @@
-#!/usr/bin/perl
-use strict;
-use warnings;
-
-print <<"EOT";
-/* Automatically generated by $0 */
-
-struct cmdname_help {
-	char name[16];
-	char help[80];
-	unsigned char group;
-};
-
-static char *common_cmd_groups[] = {
-EOT
-
-my $n = 0;
-my %grp;
-while (<>) {
-	last if /^### command list/;
-	next if (1../^### common groups/) || /^#/ || /^\s*$/;
-	chop;
-	my ($k, $v) = split ' ', $_, 2;
-	$grp{$k} = $n++;
-	print "\tN_(\"$v\"),\n";
-}
-
-print "};\n\nstatic struct cmdname_help common_cmds[] = {\n";
-
-while (<>) {
-	next if /^#/ || /^\s*$/;
-	my @tags = split;
-	my $cmd = shift @tags;
-	for my $t (@tags) {
-		if (exists $grp{$t}) {
-			my $s;
-			open my $f, '<', "Documentation/$cmd.txt" or die;
-			while (<$f>) {
-				($s) = /^$cmd - (.+)$/;
-				last if $s;
-			}
-			close $f;
-			$cmd =~ s/^git-//;
-			print "\t{\"$cmd\", N_(\"$s\"), $grp{$t}},\n";
-			last;
-		}
-	}
-}
-
-print "};\n";

generate-cmdlist.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+
+echo "/* Automatically generated by $0 */
+struct cmdname_help {
+	char name[16];
+	char help[80];
+	unsigned char group;
+};
+
+static const char *common_cmd_groups[] = {"
+
+grps=grps$$.tmp
+match=match$$.tmp
+trap "rm -f '$grps' '$match'" 0 1 2 3 15
+
+sed -n '
+	1,/^### common groups/b
+	/^### command list/q
+	/^#/b
+	/^[ 	]*$/b
+	h;s/^[^ 	][^ 	]*[ 	][ 	]*\(.*\)/	N_("\1"),/p
+	g;s/^\([^ 	][^ 	]*\)[ 	].*/\1/w '$grps'
+	' "$1"
+printf '};\n\n'
+
+n=0
+substnum=
+while read grp
+do
+	echo "^git-..*[ 	]$grp"
+	substnum="$substnum${substnum:+;}s/[ 	]$grp/$n/"
+	n=$(($n+1))
+done <"$grps" >"$match"
+
+printf 'static struct cmdname_help common_cmds[] = {\n'
+grep -f "$match" "$1" |
+sed 's/^git-//' |
+sort |
+while read cmd tags
+do
+	tag=$(echo "$tags" | sed "$substnum; s/[^0-9]//g")
+	sed -n '
+		/^NAME/,/git-'"$cmd"'/H
+		${
+			x
+			s/.*git-'"$cmd"' - \(.*\)/	{"'"$cmd"'", N_("\1"), '$tag'},/
+			p
+		}' "Documentation/git-$cmd.txt"
+done
+echo "};"