Merge 0.10->trunk

[prosody.git] / util / iterators.lua

diff --git a/util/iterators.lua b/util/iterators.lua
index aa9c3ec06a2756c404a2f5a6b1a60e6b81469bd6..bd150ff28cd3572ca407274a9bf4df2276e827df 100644 (file)
--- a/util/iterators.lua
+++ b/util/iterators.lua
@@ -11,8 +11,9 @@
 local it = {};
 
 local t_insert = table.insert;
-local select, unpack, next = select, unpack, next;
-local function pack(...) return { n = select("#", ...), ... }; end
+local select, next = select, next;
+local unpack = table.unpack or unpack; --luacheck: ignore 113
+local pack = table.pack or function (...) return { n = select("#", ...), ... }; end
 
 -- Reverse an iterator
 function it.reverse(f, s, var)
@@ -22,18 +23,18 @@ function it.reverse(f, s, var)
        while true do
                local ret = { f(s, var) };
                var = ret[1];
-               if var == nil then break; end
+               if var == nil then break; end
                t_insert(results, 1, ret);
        end
 
        -- Then return our reverse one
        local i,max = 0, #results;
-       return function (results)
-                       if i<max then
-                               i = i + 1;
-                               return unpack(results[i]);
-                       end
-               end, results;
+       return function (_results)
+               if i<max then
+                       i = i + 1;
+                       return unpack(_results[i]);
+               end
+       end, results;
 end
 
 -- Iterate only over keys in a table
@@ -47,12 +48,21 @@ end
 -- Iterate only over values in a table
 function it.values(t)
        local key, val;
-       return function (t)
-               key, val = next(t, key);
+       return function (_t)
+               key, val = next(_t, key);
                return val;
        end, t;
 end
 
+-- Iterate over the n:th return value
+function it.select(n, f, s, var)
+       return function (_s)
+               local ret = pack(f(_s, var));
+               var = ret[1];
+               return ret[n];
+       end, s, var;
+end
+
 -- Given an iterator, iterate only over unique items
 function it.unique(f, s, var)
        local set = {};
@@ -61,8 +71,8 @@ function it.unique(f, s, var)
                while true do
                        local ret = pack(f(s, var));
                        var = ret[1];
-                       if var == nil then break; end
-                       if not set[var] then
+                       if var == nil then break; end
+                       if not set[var] then
                                set[var] = true;
                                return unpack(ret, 1, ret.n);
                        end
@@ -76,7 +86,7 @@ function it.count(f, s, var)
 
        while true do
                var = f(s, var);
-               if var == nil then break; end
+               if var == nil then break; end
                x = x + 1;
        end
 
@@ -86,18 +96,18 @@ end
 -- Return the first n items an iterator returns
 function it.head(n, f, s, var)
        local c = 0;
-       return function (s, var)
+       return function (_s, _var)
                if c >= n then
                        return nil;
                end
                c = c + 1;
-               return f(s, var);
-       end, s;
+               return f(_s, _var);
+       end, s, var;
 end
 
 -- Skip the first n items an iterator returns
 function it.skip(n, f, s, var)
-       for i=1,n do
+       for _ = 1, n do
                var = f(s, var);
        end
        return f, s, var;
@@ -109,7 +119,7 @@ function it.tail(n, f, s, var)
        while true do
                local ret = pack(f(s, var));
                var = ret[1];
-               if var == nil then break; end
+               if var == nil then break; end
                results[(count%n)+1] = ret;
                count = count + 1;
        end
@@ -131,11 +141,11 @@ function it.filter(filter, f, s, var)
                local filter_value = filter;
                function filter(x) return x ~= filter_value; end
        end
-       return function (s, var)
+       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));
+               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
@@ -153,10 +163,10 @@ end
 
 -- Convert the values returned by an iterator to an array
 function it.to_array(f, s, var)
-       local t, var = {};
+       local t = {};
        while true do
                var = f(s, var);
-               if var == nil then break; end
+               if var == nil then break; end
                t_insert(t, var);
        end
        return t;
@@ -168,7 +178,7 @@ function it.to_table(f, s, var)
        local t, var2 = {};
        while true do
                var, var2 = f(s, var);
-               if var == nil then break; end
+               if var == nil then break; end
                t[var] = var2;
        end
        return t;