X-Git-Url: https://git.enpas.org/?a=blobdiff_plain;f=util%2Fiterators.lua;h=4b429163bfbdbcf963cf0d267c1d3da7b1015ac7;hb=74912f1ae3ced3725cc2d87c25b1171af586e693;hp=ba33bc80b1e5ebb417dc6513ff5eaa9317a46390;hpb=c435d0bd7afd6d625a5073cc35a2cc9500bdaf21;p=prosody.git

diff --git a/util/iterators.lua b/util/iterators.lua
index ba33bc80..4b429163 100644
--- a/util/iterators.lua
+++ b/util/iterators.lua
@@ -1,6 +1,6 @@
 -- Prosody IM
--- Copyright (C) 2008-2009 Matthew Wild
--- Copyright (C) 2008-2009 Waqas Hussain
+-- Copyright (C) 2008-2010 Matthew Wild
+-- Copyright (C) 2008-2010 Waqas Hussain
 -- 
 -- This project is MIT/X11 licensed. Please see the
 -- COPYING file in the source package for more information.
@@ -8,8 +8,14 @@
 
 --[[ Iterators ]]--
 
+local it = {};
+
+local t_insert = table.insert;
+local select, unpack, next = select, unpack, next;
+local function pack(...) return { n = select("#", ...), ... }; end
+
 -- Reverse an iterator
-function reverse(f, s, var)
+function it.reverse(f, s, var)
 	local results = {};
 
 	-- First call the normal iterator
@@ -17,7 +23,7 @@ function reverse(f, s, var)
 		local ret = { f(s, var) };
 		var = ret[1];
 	        if var == nil then break; end
-		table.insert(results, 1, ret);
+		t_insert(results, 1, ret);
 	end
 	
 	-- Then return our reverse one
@@ -34,12 +40,12 @@ end
 local function _keys_it(t, key)
 	return (next(t, key));
 end
-function keys(t)
+function it.keys(t)
 	return _keys_it, t;
 end
 
 -- Iterate only over values in a table
-function values(t)
+function it.values(t)
 	local key, val;
 	return function (t)
 		key, val = next(t, key);
@@ -48,38 +54,37 @@ function values(t)
 end
 
 -- Given an iterator, iterate only over unique items
-function unique(f, s, var)
+function it.unique(f, s, var)
 	local set = {};
 	
 	return function ()
 		while true do
-			local ret = { f(s, var) };
+			local ret = pack(f(s, var));
 			var = ret[1];
 		        if var == nil then break; end
 		        if not set[var] then
 				set[var] = true;
-				return var;
+				return unpack(ret, 1, ret.n);
 			end
 		end
 	end;
 end
 
 --[[ Return the number of items an iterator returns ]]--
-function count(f, s, var)
+function it.count(f, s, var)
 	local x = 0;
 	
 	while true do
-		local ret = { f(s, var) };
-		var = ret[1];
+		var = f(s, var);
 	        if var == nil then break; end
 		x = x + 1;
-	end	
+	end
 	
 	return x;
 end
 
 -- Return the first n items an iterator returns
-function head(n, f, s, var)
+function it.head(n, f, s, var)
 	local c = 0;
 	return function (s, var)
 		if c >= n then
@@ -90,10 +95,19 @@ function head(n, f, s, var)
 	end, s;
 end
 
-function tail(n, f, s, var)
+-- Skip the first n items an iterator returns
+function it.skip(n, f, s, var)
+	for i=1,n do
+		var = f(s, var);
+	end
+	return f, s, var;
+end
+
+-- Return the last n items an iterator returns
+function it.tail(n, f, s, var)
 	local results, count = {}, 0;
 	while true do
-		local ret = { f(s, var) };
+		local ret = pack(f(s, var));
 		var = ret[1];
 	        if var == nil then break; end
 		results[(count%n)+1] = ret;
@@ -106,26 +120,52 @@ function tail(n, f, s, var)
 	return function ()
 		pos = pos + 1;
 		if pos > n then return nil; end
-		return unpack(results[((count-1+pos)%n)+1]);
+		local ret = results[((count-1+pos)%n)+1];
+		return unpack(ret, 1, ret.n);
 	end
-	--return reverse(head(n, reverse(f, s, var)));
+	--return reverse(head(n, reverse(f, s, var))); -- !
+end
+
+function it.filter(filter, f, s, var)
+	if type(filter) ~= "function" then
+		local filter_value = filter;
+		function filter(x) return x ~= filter_value; end
+	end
+	return function (s, var)
+		local ret;
+		repeat ret = pack(f(s, var));
+			var = ret[1];
+		until var == nil or filter(unpack(ret, 1, ret.n));
+		return unpack(ret, 1, ret.n);
+	end, s, var;
+end
+
+local function _ripairs_iter(t, key) if key > 1 then return key-1, t[key-1]; end end
+function it.ripairs(t)
+	return _ripairs_iter, t, #t+1;
+end
+
+local function _range_iter(max, curr) if curr < max then return curr + 1; end end
+function it.range(x, y)
+	if not y then x, y = 1, x; end -- Default to 1..x if y not given
+	return _range_iter, y, x-1;
 end
 
 -- Convert the values returned by an iterator to an array
-function it2array(f, s, var)
+function it.to_array(f, s, var)
 	local t, var = {};
 	while true do
 		var = f(s, var);
 	        if var == nil then break; end
-		table.insert(t, var);
+		t_insert(t, var);
 	end
 	return t;
 end
 
--- Treat the return of an iterator as key,value pairs, 
+-- Treat the return of an iterator as key,value pairs,
 -- and build a table
-function it2table(f, s, var)
-	local t, var = {};
+function it.to_table(f, s, var)
+	local t, var2 = {};
 	while true do
 		var, var2 = f(s, var);
 	        if var == nil then break; end
@@ -133,3 +173,5 @@ function it2table(f, s, var)
 	end
 	return t;
 end
+
+return it;