# 
# 
# add_file "contrib/ext_hooks.lua.in"
#  content [9465ba457136d50edccaad82bdab09870e6bff77]
# 
# add_file "contrib/ext_hooks_expand.pl"
#  content [80d323d81b14a00ba5aeeeafb18a2474a157262b]
# 
# patch "ChangeLog"
#  from [7d1211b293f94886ad3e3a3c732980ad4cc94807]
#    to [2d7c5ffe4b75e6408186b26ff7d45aa46889eaae]
# 
# patch "contrib/README"
#  from [ccc023e05e18cba04e516b2f4b0d594bc55c89c6]
#    to [03b97be886f1ea1dce0689113b1364406a87c9ad]
# 
============================================================
--- contrib/ext_hooks.lua.in	9465ba457136d50edccaad82bdab09870e6bff77
+++ contrib/ext_hooks.lua.in	9465ba457136d50edccaad82bdab09870e6bff77
@@ -0,0 +1,75 @@
+-- this is an add-on to the standard set of lua hooks for monotone;
+-- the intention is to store the hooks in arrays of hooks and to load
+-- extra .lua files from a directory given by the environment variable
+-- $MTN_LUAHOOKSDIR
+--
+-- Hooks are supposed to be added using the following syntax:
+--
+--	add_hook("edit_comment",
+--               function (commentary, user_log_message)
+--                  -- do whatever needs to be done
+--               end
+--              )
+--
+-- The existing standard hooks are automatically added as the first item
+-- to each array of hooks, and will be therefore executed first.
+--
+-- Also, should the standard hook functions be defined by any of the loaded
+-- .lua files, the last definition will be added as the last item to each
+-- array of hooks.
+--
+-- It's perfectly possible to have several implementations of the same
+-- hook.  Those will be executed in the same order the were added as hooks.
+--
+-- Any non-nil result is stored in a global variable named like the hook
+-- with "res_" prepended.  For example, any non-nil result from "edit_comment"
+-- hooks is stored in the global variable res_edit_comment.  When all
+-- "edit_comment" hooks have been executed, the contents of res_edit_comment
+-- is returned by the global edit_comment function.  The same goes for all
+-- other hook executors.
+--
+-- ----------------------------------------------------------------------------
+
+-- Define the table that will contain pointers to all the hooks.
+-- Each entry is the tuple <name, fn-table>, where {name} is the name
+-- of the hook in question and fn-table is a table of functions.
+mtn_luahooks = {}
+
+-- Define functions to manipulate the table of hooks.
+function add_hook(name, fun)
+   if name ~= nil and fun ~= nil then
+      if mtn_luahooks[name] == nil then mtn_luahooks[name] = {} end
+      table.insert(mtn_luahooks[name], fun)
+   end
+end
+
+_known_hooks = {
+   "@@HOOKS_LIST@@",
+}   
+function _add_known_hooks()
+   for i,name in pairs(_known_hooks) do
+      local fntab = getfenv(0)
+      local fn = fntab[name]
+      fntab[name] = nil
+      setfenv(0, fntab)
+      add_hook(name,fn)
+   end
+end
+
+-- This stores the definitions of all the known hooks first in the table.
+_add_known_hooks()
+
+-- Load all the *.lua files found in $MTN_LUAHOOKSDIR if that variable is
+-- defined.
+_mtn_luahooksdir = os.getenv("MTN_LUAHOOKSDIR")
+if _mtn_luahooksdir ~= nil and _mtn_luahooksdir ~= "" then
+   includedirpattern(_mtn_luahooksdir, "*.lua")
+end
+
+-- If anyone was foolish enough to define a hook function directly instead
+-- of using "add_hook", the last will win and will be inserted in the table
+-- of hooks.
+_add_known_hooks()
+
+-- Finally, redefine all known functions to use the hooks to do their job
+@@HOOKS_FUNCTIONS@@
============================================================
--- contrib/ext_hooks_expand.pl	80d323d81b14a00ba5aeeeafb18a2474a157262b
+++ contrib/ext_hooks_expand.pl	80d323d81b14a00ba5aeeeafb18a2474a157262b
@@ -0,0 +1,96 @@
+#! /usr/bin/perl
+
+use warnings;
+use strict;
+use File::Basename;
+use File::Spec;
+
+my $here = dirname($0);
+my $there = File::Spec->catdir($here,File::Spec->updir());
+my $monotone_texi = File::Spec->catfile($there, "monotone.texi");
+my $ext_hooks_lua_in = File::Spec->catfile($here, "ext_hooks.lua.in");
+my $ext_hooks_lua = File::Spec->catfile($here, "ext_hooks.lua");
+
+# Format:  $name => $arglist
+my %hooks = ();
+
+open INPUT, $monotone_texi ||
+    die "Couldn't open $monotone_texi for reading: $!\n";
+
+# First, read until we find the Hooks section
+while(<INPUT>) {
+    chomp;
+    last if (/address@hidden/);
+}
+
+# Now, parse all the hooks docs until we find the Additional Lua Functions
+# section
+while(<INPUT>) {
+    chomp;
+    last if (/address@hidden/);
+    if (/address@hidden(\w+)\s*\((address@hidden(,address@hidden)*)?\)\s*$/) {
+	my $name = $1;
+	my $arglist = "";
+	if (defined $2) {
+	    $arglist = join(", ",
+			    map {
+				my $x = $_;
+				$x =~ s/address@hidden(\w+)\}\s*$/$1/;
+				$x;
+			    } split(/,\s*/, $2));
+	}
+	$hooks{$name} = $arglist;
+    }
+}
+
+close INPUT;
+
+foreach my $n (sort keys %hooks) {
+    print $n," => \"",$hooks{$n},"\"\n";
+}
+
+open INPUT, $ext_hooks_lua_in ||
+    die "Couldn't open $ext_hooks_lua_in for reading: $!\n";
+open OUTPUT, ">$ext_hooks_lua" ||
+    die "Couldn't open $ext_hooks_lua for writing: $!\n";
+
+# Format : $name => [ list of strings ]
+my %expansions = ( HOOKS_LIST => [],
+		   HOOKS_FUNCTIONS => []);
+
+foreach my $n (sort keys %hooks) {
+    push(@{$expansions{HOOKS_LIST}}, $n);
+    push(@{$expansions{HOOKS_FUNCTIONS}},
+"function $n ($hooks{$n})
+   local i
+   local fn
+   res_$n = nil
+   for i,fn in pairs(mtn_luahooks[\"$n\"]) do
+      res = fn($hooks{$n})
+      if res ~= nil then res_$n = res end
+   end
+   return res_$n
+end"
+	 );
+}
+
+while(<INPUT>) {
+    chomp;
+    if (/^(.*)address@hidden@(\w+)address@hidden@(.*)$/) {
+	my $prefix = $1;
+	my $listname = $2;
+	my $postfix = $3;
+	if (defined $expansions{$listname}) {
+	    foreach my $item (@{$expansions{$listname}}) {
+		print OUTPUT $prefix,$item,$postfix,"\n";
+	    }
+	} else {
+	    print OUTPUT $prefix,$listname,$postfix,"\n";
+	}
+    } else {
+	print OUTPUT $_,"\n";
+    }
+}
+
+close OUTPUT;
+close INPUT;
============================================================
--- ChangeLog	7d1211b293f94886ad3e3a3c732980ad4cc94807
+++ ChangeLog	2d7c5ffe4b75e6408186b26ff7d45aa46889eaae
@@ -1,3 +1,14 @@
+2006-11-16  Richard Levitte  <address@hidden>
+
+	* contrib/ext_hooks.lua.in, contrib/ext_hooks_expand.pl: New
+	files that implement a system that allows easy addition of hooks
+	implementations without having to edit any file. You need to
+	run the perl script contrib/ext_hooks_expand.pl to produce the
+	file contrib/ext_hooks.lua, using contrib/ext_hooks.lua.in as
+	a template and the hook function definitions found in
+	monotone.texi.
+	* README: Add a small blurb about the above files.
+
 2006-11-15  Richard Levitte  <address@hidden>
 
 	* lua.cc (LUAEXT): Implement includedirpattern(), which is like
============================================================
--- contrib/README	ccc023e05e18cba04e516b2f4b0d594bc55c89c6
+++ contrib/README	03b97be886f1ea1dce0689113b1364406a87c9ad
@@ -34,3 +34,10 @@ licenses.
 
   -- mtn_cheat_sheet.svg: A SVG image inspired by Mercurial's QuickStart Guides
      (http://people.type-z.org/seb/mercurial/v1.0/)
+
+  -- ext_hooks.lua.in, ext_hooks_expand.pl: run ext_hooks_expand.pl and you
+     will get ext_hooks.lua, a hooks system that allows loading several
+     implementations of the same hooks from a bunch of .lua files stored in
+     a directory pointed at by $MTN_LUAHOOKSDIR.  Hooks are commonly added
+     using the function add_hook().  There is simple documentation at the
+     top of ext_hooks.lua.in.