util.array: Per-array methods now always mutate the array, array.* return a mutated...

diff --git a/util/array.lua b/util/array.lua
index ce5ce07747f1685573291e6973254f39d0848b50..ae3a0b5bdf178f247356e093eef15c512a56f64b 100644 (file)
--- a/util/array.lua
+++ b/util/array.lua
@@ -6,9 +6,14 @@
 -- COPYING file in the source package for more information.
 --
 
+local t_insert, t_sort, t_remove, t_concat 
+       = table.insert, table.sort, table.remove, table.concat;
+
 local array = {};
+local array_base = {};
+local array_methods = {};
+local array_mt = { __index = array_methods, __tostring = function (array) return array:concat(", "); end };
 
-local array_mt = { __index = array, __tostring = function (array) return array:concat(", "); end };
 local function new_array(_, t)
        return setmetatable(t or {}, array_mt);
 end
@@ -20,36 +25,36 @@ end
 
 setmetatable(array, { __call = new_array });
 
-function array:map(func, t2)
-       local t2 = t2 or array{};
-       for k,v in ipairs(self) do
-               t2[k] = func(v);
+function array_base.map(outa, ina, func)
+       for k,v in ipairs(ina) do
+               outa[k] = func(v);
        end
-       return t2;
+       return outa;
 end
 
-function array:filter(func, t2)
-       local t2 = t2 or array{};
-       for k,v in ipairs(self) do
+function array_base.filter(outa, ina, func)
+       for k,v in ipairs(ina) do
                if func(v) then
-                       t2:push(v);
+                       outa:push(v);
                end
        end
-       return t2;
+       return outa;
 end
 
+function array_base.sort(outa, ina, ...)
+       if ina ~= outa then
+               outa:append(ina);
+       end
+       t_sort(outa, ...);
+       return outa;
+end
 
-array.push = table.insert;
-array.pop = table.remove;
-array.sort = table.sort;
-array.concat = table.concat;
-array.length = function (t) return #t; end
-
-function array:random()
+--- These methods only mutate
+function array_methods:random()
        return self[math.random(1,#self)];
 end
 
-function array:shuffle()
+function array_methods:shuffle(outa, ina)
        local len = #self;
        for i=1,#self do
                local r = math.random(i,len);
@@ -58,7 +63,7 @@ function array:shuffle()
        return self;
 end
 
-function array:reverse()
+function array_methods:reverse()
        local len = #self-1;
        for i=len,1,-1 do
                self:push(self[i]);
@@ -67,7 +72,7 @@ function array:reverse()
        return self;
 end
 
-function array:append(array)
+function array_methods:append(array)
        local len,len2  = #self, #array;
        for i=1,len2 do
                self[len+i] = array[i];
@@ -75,6 +80,12 @@ function array:append(array)
        return self;
 end
 
+array_methods.push = table.insert;
+array_methods.pop = table.remove;
+array_methods.concat = table.concat;
+array_methods.length = function (t) return #t; end
+
+--- These methods always create a new array
 function array.collect(f, s, var)
        local t, var = {};
        while true do
@@ -85,6 +96,23 @@ function array.collect(f, s, var)
        return setmetatable(t, array_mt);
 end
 
+---
+
+-- Setup methods from array_base
+for method, f in pairs(array_base) do
+       local method = method; -- Yes, this is necessary :)
+       local base_method = f;
+       -- Setup global array method which makes new array
+       array[method] = function (old_a, ...)
+               local a = new_array();
+               return base_method(a, old_a, ...);
+       end
+       -- Setup per-array (mutating) method
+       array_methods[method] = function (self, ...)
+               return base_method(self, self, ...);
+       end
+end
+
 _G.array = array;
 module("array");