[PATCH v2 3/3] git.txt: add list of guides

["Philippe Blain via GitGitGadget" <gitgitgadget@gmail.com>]

From: Philippe Blain <levraiphilippeblain@gmail.com>

Not all man5/man7 guides are mentioned in the 'git(1)' documentation,
which makes the missing ones somewhat hard to find.

Add a list of the guides to git(1) by leveraging the existing
`Documentation/cmd-list.perl` script to generate a file `cmds-guide.txt`
which gets included in git.txt.

Instead of hard-coding the list of command categories in both
`Documentation/Makefile` and `Documentation/cmd-list.perl`, make the
Makefile the authoritative source and tweak `cmd-list.perl` so that it
receives the list of command categories as argument.

Also, do not hard-code the manual section '1'. Instead, use a regex so
that the manual section is discovered from the first line of each
`git*.txt` file.

This addition was hinted at in 1b81d8cb19 (help: use command-list.txt for
the source of guides, 2018-05-20).

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
---
 Documentation/Makefile      |  3 ++-
 Documentation/cmd-list.perl | 27 ++++++++++++++-------------
 Documentation/git.txt       |  7 +++++++
 3 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/Documentation/Makefile b/Documentation/Makefile
index 39f6fc8de7..80d1908a44 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -295,6 +295,7 @@ cmds_txt = cmds-ancillaryinterrogators.txt \
 	cmds-plumbingmanipulators.txt \
 	cmds-synchingrepositories.txt \
 	cmds-synchelpers.txt \
+	cmds-guide.txt \
 	cmds-purehelpers.txt \
 	cmds-foreignscminterface.txt
 
@@ -302,7 +303,7 @@ $(cmds_txt): cmd-list.made
 
 cmd-list.made: cmd-list.perl ../command-list.txt $(MAN1_TXT)
 	$(QUIET_GEN)$(RM) $@ && \
-	$(PERL_PATH) ./cmd-list.perl ../command-list.txt $(QUIET_STDERR) && \
+	$(PERL_PATH) ./cmd-list.perl ../command-list.txt $(cmds_txt) $(QUIET_STDERR) && \
 	date >$@
 
 mergetools_txt = mergetools-diff.txt mergetools-merge.txt
diff --git a/Documentation/cmd-list.perl b/Documentation/cmd-list.perl
index 5aa73cfe45..af5da45d28 100755
--- a/Documentation/cmd-list.perl
+++ b/Documentation/cmd-list.perl
@@ -6,9 +6,14 @@ sub format_one {
 	my ($out, $nameattr) = @_;
 	my ($name, $attr) = @$nameattr;
 	my ($state, $description);
+	my $mansection;
 	$state = 0;
 	open I, '<', "$name.txt" or die "No such file $name.txt";
 	while (<I>) {
+		if (/^git[a-z0-9-]*\(([0-9])\)$/) {
+			$mansection = $1;
+			next;
+		}
 		if (/^NAME$/) {
 			$state = 1;
 			next;
@@ -27,7 +32,7 @@ sub format_one {
 		die "No description found in $name.txt";
 	}
 	if (my ($verify_name, $text) = ($description =~ /^($name) - (.*)/)) {
-		print $out "linkgit:$name\[1\]::\n\t";
+		print $out "linkgit:$name\[$mansection\]::\n\t";
 		if ($attr =~ / deprecated /) {
 			print $out "(deprecated) ";
 		}
@@ -38,12 +43,15 @@ sub format_one {
 	}
 }
 
-while (<>) {
+my ($input, @categories) = @ARGV;
+
+open IN, "<$input";
+while (<IN>) {
 	last if /^### command list/;
 }
 
 my %cmds = ();
-for (sort <>) {
+for (sort <IN>) {
 	next if /^#/;
 
 	chomp;
@@ -51,17 +59,10 @@ sub format_one {
 	$attr = '' unless defined $attr;
 	push @{$cmds{$cat}}, [$name, " $attr "];
 }
+close IN;
 
-for my $cat (qw(ancillaryinterrogators
-		ancillarymanipulators
-		mainporcelain
-		plumbinginterrogators
-		plumbingmanipulators
-		synchingrepositories
-		foreignscminterface
-		purehelpers
-		synchelpers)) {
-	my $out = "cmds-$cat.txt";
+for my $out (@categories) {
+	my ($cat) = $out =~ /^cmds-(.*)\.txt$/;
 	open O, '>', "$out+" or die "Cannot open output file $out+";
 	for (@{$cmds{$cat}}) {
 		format_one(\*O, $_);
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 3e50065198..81349a84e7 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -304,6 +304,13 @@ users typically do not use them directly.
 
 include::cmds-purehelpers.txt[]
 
+Guides
+------
+
+The following documentation pages are guides about Git concepts.
+
+include::cmds-guide.txt[]
+
 
 Configuration Mechanism
 -----------------------
-- 
gitgitgadget