diff --git a/program.own b/program.own
index 9aac799..859a3c3 100644
--- a/program.own
+++ b/program.own
@@ -1,5 +1,7 @@
 use "math"
 use "std"
+use "functional"
+
 word = 2 + 2
 word2 = PI + word
 str = "a" * 5 + "ba" * 7 + "\n"
@@ -117,3 +119,9 @@ thread(::inthread)
 def inthread() = echo("this is a thread")
 thread(def (str) { println str }, "this is a thread with arguments")
 
+println "functional"
+nums = [1,2,3,4,5,6,7,8,9,10]
+nums = filter(nums, def(x) = x % 2 == 0)
+squares = map(nums, def(x) = x * x)
+foreach(squares, ::echo)
+println "Sum: " + reduce(squares, 0, def(x, y) = x + y)
\ No newline at end of file
diff --git a/src/com/annimon/ownlang/lib/ArrayValue.java b/src/com/annimon/ownlang/lib/ArrayValue.java
index 427c17d..e34b8ce 100644
--- a/src/com/annimon/ownlang/lib/ArrayValue.java
+++ b/src/com/annimon/ownlang/lib/ArrayValue.java
@@ -47,6 +47,10 @@ public final class ArrayValue implements Value, Iterable<Value> {
         return Types.ARRAY;
     }
     
+    public int size() {
+        return elements.length;
+    }
+    
     public Value get(int index) {
         return elements[index];
     }
diff --git a/src/com/annimon/ownlang/lib/MapValue.java b/src/com/annimon/ownlang/lib/MapValue.java
index 1c77a97..c55bd94 100644
--- a/src/com/annimon/ownlang/lib/MapValue.java
+++ b/src/com/annimon/ownlang/lib/MapValue.java
@@ -25,6 +25,10 @@ public class MapValue implements Value, Iterable<Map.Entry<Value, Value>> {
     public int type() {
         return Types.MAP;
     }
+    
+    public int size() {
+        return map.size();
+    }
 
     public Value get(Value key) {
         return map.get(key);
diff --git a/src/com/annimon/ownlang/lib/modules/functional.java b/src/com/annimon/ownlang/lib/modules/functional.java
new file mode 100644
index 0000000..e5bc229
--- /dev/null
+++ b/src/com/annimon/ownlang/lib/modules/functional.java
@@ -0,0 +1,19 @@
+package com.annimon.ownlang.lib.modules;
+
+import com.annimon.ownlang.lib.*;
+import com.annimon.ownlang.lib.modules.functions.*;
+
+/**
+ *
+ * @author aNNiMON
+ */
+public final class functional implements Module {
+
+    @Override
+    public void init() {
+        Functions.set("foreach", new functional_foreach());
+        Functions.set("map", new functional_map());
+        Functions.set("reduce", new functional_reduce());
+        Functions.set("filter", new functional_filter());
+    }
+}
diff --git a/src/com/annimon/ownlang/lib/modules/functions/functional_filter.java b/src/com/annimon/ownlang/lib/modules/functions/functional_filter.java
new file mode 100644
index 0000000..c1f7ed9
--- /dev/null
+++ b/src/com/annimon/ownlang/lib/modules/functions/functional_filter.java
@@ -0,0 +1,52 @@
+package com.annimon.ownlang.lib.modules.functions;
+
+import com.annimon.ownlang.lib.*;
+import java.util.ArrayList;
+import java.util.List;
+
+import java.util.Map;
+
+public final class functional_filter implements Function {
+
+    @Override
+    public Value execute(Value... args) {
+        if (args.length < 2) throw new RuntimeException("At least two args expected");
+        
+        if (args[1].type() != Types.FUNCTION) {
+            throw new RuntimeException("Function expected in second arg");
+        }
+        final Value container = args[0];
+        final Function consumer = ((FunctionValue) args[1]).getValue();
+        if (container.type() == Types.ARRAY) {
+            return filterArray((ArrayValue) container, consumer);
+        }
+        
+        if (container.type() == Types.MAP) {
+            return filterMap((MapValue) container, consumer);
+        }
+
+        throw new RuntimeException("Invalid first argument. Array or map exprected");
+    }
+    
+    private Value filterArray(ArrayValue array, Function predicate) {
+        final int size = array.size();
+        final List<Value> values = new ArrayList<Value>(size);
+        for (Value value : array) {
+            if (predicate.execute(value) != NumberValue.ZERO) {
+                values.add(value);
+            }
+        }
+        final int newSize = values.size();
+        return new ArrayValue(values.toArray(new Value[newSize]));
+    }
+    
+    private Value filterMap(MapValue map, Function predicate) {
+        final MapValue result = new MapValue(map.size());
+        for (Map.Entry<Value, Value> element : map) {
+            if (predicate.execute(element.getKey(), element.getValue()) != NumberValue.ZERO) {
+                result.set(element.getKey(), element.getValue());
+            }
+        }
+        return result;
+    }
+}
\ No newline at end of file
diff --git a/src/com/annimon/ownlang/lib/modules/functions/functional_foreach.java b/src/com/annimon/ownlang/lib/modules/functions/functional_foreach.java
new file mode 100644
index 0000000..bf9bf33
--- /dev/null
+++ b/src/com/annimon/ownlang/lib/modules/functions/functional_foreach.java
@@ -0,0 +1,34 @@
+package com.annimon.ownlang.lib.modules.functions;
+
+import com.annimon.ownlang.lib.*;
+
+import java.util.Map;
+
+public final class functional_foreach implements Function {
+
+    @Override
+    public Value execute(Value... args) {
+        if (args.length != 2) throw new RuntimeException("Two args expected");
+        
+        if (args[1].type() != Types.FUNCTION) {
+            throw new RuntimeException("Function expected in second arg");
+        }
+        final Value container = args[0];
+        final Function consumer = ((FunctionValue) args[1]).getValue();
+        if (container.type() == Types.ARRAY) {
+            final ArrayValue array = (ArrayValue) container;
+            for (Value element : array) {
+                consumer.execute(element);
+            }
+            return NumberValue.ZERO;
+        }
+        if (container.type() == Types.MAP) {
+            final MapValue map = (MapValue) container;
+            for (Map.Entry<Value, Value> element : map) {
+                consumer.execute(element.getKey(), element.getValue());
+            }
+            return NumberValue.ZERO;
+        }
+        throw new RuntimeException("Invalid first argument. Array or map exprected");
+    }
+}
\ No newline at end of file
diff --git a/src/com/annimon/ownlang/lib/modules/functions/functional_map.java b/src/com/annimon/ownlang/lib/modules/functions/functional_map.java
new file mode 100644
index 0000000..980106c
--- /dev/null
+++ b/src/com/annimon/ownlang/lib/modules/functions/functional_map.java
@@ -0,0 +1,55 @@
+package com.annimon.ownlang.lib.modules.functions;
+
+import com.annimon.ownlang.lib.*;
+
+import java.util.Map;
+
+public final class functional_map implements Function {
+
+    @Override
+    public Value execute(Value... args) {
+        if (args.length < 2) throw new RuntimeException("At least two args expected");
+        
+        final Value container = args[0];
+        if (container.type() == Types.ARRAY) {
+            if (args[1].type() != Types.FUNCTION) {
+                throw new RuntimeException("Function expected in second arg");
+            }
+            final Function mapper = ((FunctionValue) args[1]).getValue();
+            return mapArray((ArrayValue) container, mapper);
+        }
+        
+        if (container.type() == Types.MAP) {
+            if (args[1].type() != Types.FUNCTION) {
+                throw new RuntimeException("Function expected in second arg");
+            }
+            if (args[2].type() != Types.FUNCTION) {
+                throw new RuntimeException("Function expected in third arg");
+            }
+            final Function keyMapper = ((FunctionValue) args[1]).getValue();
+            final Function valueMapper = ((FunctionValue) args[2]).getValue();
+            return mapMap((MapValue) container, keyMapper, valueMapper);
+        }
+
+        throw new RuntimeException("Invalid first argument. Array or map exprected");
+    }
+    
+    private Value mapArray(ArrayValue array, Function mapper) {
+        final int size = array.size();
+        final ArrayValue result = new ArrayValue(size);
+        for (int i = 0; i < size; i++) {
+            result.set(i, mapper.execute(array.get(i)));
+        }
+        return result;
+    }
+    
+    private Value mapMap(MapValue map, Function keyMapper, Function valueMapper) {
+        final MapValue result = new MapValue(map.size());
+        for (Map.Entry<Value, Value> element : map) {
+            final Value newKey = keyMapper.execute(element.getKey());
+            final Value newValue = valueMapper.execute(element.getValue());
+            result.set(newKey, newValue);
+        }
+        return result;
+    }
+}
\ No newline at end of file
diff --git a/src/com/annimon/ownlang/lib/modules/functions/functional_reduce.java b/src/com/annimon/ownlang/lib/modules/functions/functional_reduce.java
new file mode 100644
index 0000000..7a886eb
--- /dev/null
+++ b/src/com/annimon/ownlang/lib/modules/functions/functional_reduce.java
@@ -0,0 +1,37 @@
+package com.annimon.ownlang.lib.modules.functions;
+
+import com.annimon.ownlang.lib.*;
+
+import java.util.Map;
+
+public final class functional_reduce implements Function {
+
+    @Override
+    public Value execute(Value... args) {
+        if (args.length != 3) throw new RuntimeException("Three args expected");
+        
+        if (args[2].type() != Types.FUNCTION) {
+            throw new RuntimeException("Function expected in third arg");
+        }
+        final Value container = args[0];
+        final Value identity = args[1];
+        final Function accumulator = ((FunctionValue) args[2]).getValue();
+        if (container.type() == Types.ARRAY) {
+            Value result = identity;
+            final ArrayValue array = (ArrayValue) container;
+            for (Value element : array) {
+                result = accumulator.execute(result, element);
+            }
+            return result;
+        }
+        if (container.type() == Types.MAP) {
+            Value result = identity;
+            final MapValue map = (MapValue) container;
+            for (Map.Entry<Value, Value> element : map) {
+                result = accumulator.execute(result, element.getKey(), element.getValue());
+            }
+            return result;
+        }
+        throw new RuntimeException("Invalid first argument. Array or map exprected");
+    }
+}
\ No newline at end of file
diff --git a/src/com/annimon/ownlang/lib/modules/std.java b/src/com/annimon/ownlang/lib/modules/std.java
index dfa4409..3919698 100644
--- a/src/com/annimon/ownlang/lib/modules/std.java
+++ b/src/com/annimon/ownlang/lib/modules/std.java
@@ -12,7 +12,6 @@ public final class std implements Module {
     @Override
     public void init() {
         Functions.set("echo", new std_echo());
-        Functions.set("foreach", new std_foreach());
         Functions.set("newarray", new std_newarray());
         Functions.set("rand", new std_rand());
         Functions.set("sleep", new std_sleep());