Merge 0.9->trunk

[prosody.git] / util / iterators.lua

diff --git a/util/iterators.lua b/util/iterators.lua
index 1f6aacb81a4d36e77ba23429ff2001f6cdf14ad3..aa9c3ec06a2756c404a2f5a6b1a60e6b81469bd6 100644 (file)
--- a/util/iterators.lua
+++ b/util/iterators.lua
@@ -1,7 +1,7 @@
 -- Prosody IM
 -- 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.
 --
@@ -10,6 +10,10 @@
 
 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 it.reverse(f, s, var)
        local results = {};
@@ -19,9 +23,9 @@ function it.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
        local i,max = 0, #results;
        return function (results)
@@ -52,15 +56,15 @@ end
 -- Given an iterator, iterate only over unique items
 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;
@@ -69,14 +73,13 @@ end
 --[[ Return the number of items an iterator returns ]]--
 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
-       
+
        return x;
 end
 
@@ -104,7 +107,7 @@ end
 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;
@@ -117,9 +120,24 @@ function it.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
@@ -139,7 +157,7 @@ function it.to_array(f, s, 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