diff --git a/translator/src/main/kotlin/org/kotlinnative/translator/FunctionCodegen.kt b/translator/src/main/kotlin/org/kotlinnative/translator/FunctionCodegen.kt
index 29ad1ac1c7b..f95bf58fbfe 100644
--- a/translator/src/main/kotlin/org/kotlinnative/translator/FunctionCodegen.kt
+++ b/translator/src/main/kotlin/org/kotlinnative/translator/FunctionCodegen.kt
@@ -30,20 +30,42 @@ class FunctionCodegen(val state: TranslationState, val function: KtNamedFunction
     }
 
     fun generate() {
-        generateDeclaration(function)
+        if (generateDeclaration(function)) {
+            return
+        }
+
         codeBuilder.addStartExpression()
         expressionWalker(function.bodyExpression)
+
+        if (returnType == "void") {
+            codeBuilder.addVoidReturn()
+        }
+
         codeBuilder.addEndExpression()
     }
 
-    private fun generateDeclaration(function: KtNamedFunction) {
-        codeBuilder.addLLVMCode(LLVMDescriptorGenerate(function.fqName.toString(), args, returnType))
+    private fun generateDeclaration(function: KtNamedFunction): Boolean {
+        var external = false
+
+        var keyword = function.firstChild
+        while (keyword != null) {
+            if (keyword.text == "external") {
+                external = true
+                break
+            }
+
+            keyword = keyword.getNextSiblingIgnoringWhitespaceAndComments()
+        }
+
+        codeBuilder.addLLVMCode(LLVMFunctionDescriptor(function.fqName.toString(), args, returnType, external))
+        return external
     }
 
     private fun expressionWalker(expr: PsiElement?) {
         when (expr) {
             is KtBlockExpression -> expressionWalker(expr.firstChild)
             is KtProperty -> evaluateLeafPsiElement(expr.firstChild as LeafPsiElement)
+            is KtCallExpression -> codeBuilder.addLLVMCode(evaluateCallExpression(expr).toString())
             is PsiElement -> evaluateExpression(expr.firstChild)
             null -> return
             else -> UnsupportedOperationException()
diff --git a/translator/src/main/kotlin/org/kotlinnative/translator/exceptions/UnimplementedException.kt b/translator/src/main/kotlin/org/kotlinnative/translator/exceptions/UnimplementedException.kt
new file mode 100644
index 00000000000..0906653fcd6
--- /dev/null
+++ b/translator/src/main/kotlin/org/kotlinnative/translator/exceptions/UnimplementedException.kt
@@ -0,0 +1,3 @@
+package org.kotlinnative.translator.exceptions
+
+class UnimplementedException() : Exception()
diff --git a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/LLVMBuilder.kt b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/LLVMBuilder.kt
index b8cc7c7a132..f0e1ec063fc 100644
--- a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/LLVMBuilder.kt
+++ b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/LLVMBuilder.kt
@@ -56,6 +56,10 @@ class LLVMBuilder {
         llvmCode.appendln("ret i32 $llvmVariable")
     }
 
+    fun addVoidReturn() {
+        llvmCode.appendln("ret void")
+    }
+
     override fun toString(): String {
         return llvmCode.toString()
     }
diff --git a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/LLVMVariable.kt b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/LLVMVariable.kt
index e711857d9b2..f1b59b167d8 100644
--- a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/LLVMVariable.kt
+++ b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/LLVMVariable.kt
@@ -4,8 +4,6 @@ import org.kotlinnative.translator.llvm.types.LLVMType
 
 class LLVMVariable(val label: String, val type: LLVMType? = null) : LLVMNode() {
 
-    override fun toString(): String {
-        return label
-    }
+    override fun toString(): String = label
 
 }
\ No newline at end of file
diff --git a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/generators.kt b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/generators.kt
index ab93e42d785..a73c923115e 100644
--- a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/generators.kt
+++ b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/generators.kt
@@ -2,10 +2,14 @@ package org.kotlinnative.translator.llvm
 
 import org.kotlinnative.translator.utils.FunctionArgument
 
-fun LLVMDescriptorGenerate(name: String, argTypes: List<FunctionArgument>?, returnType: String) =
-        "define $returnType @$name(${argTypes?.mapIndexed { i: Int, s: FunctionArgument -> "${s.type} %tmp.${s.name}" }?.joinToString() ?: "" })"
+fun LLVMFunctionDescriptor(name: String, argTypes: List<FunctionArgument>?, returnType: String, declare: Boolean = false) =
+        "${ if (declare) "declare" else "define"} $returnType @$name(${
+            argTypes?.mapIndexed { i: Int, s: FunctionArgument -> "${s.type} %tmp.${s.name}"
+        }?.joinToString() ?: "" })"
+
 
 fun LLVMMapStandardType(type: String) = when(type) {
     "Int" -> "i32"
+    "Unit" -> "void"
     else -> "%$type*"
 }
\ No newline at end of file
diff --git a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMDoubleType.kt b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMDoubleType.kt
index b0c21d2834b..460d86215cd 100644
--- a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMDoubleType.kt
+++ b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMDoubleType.kt
@@ -6,20 +6,17 @@ import org.kotlinnative.translator.llvm.LLVMVariable
 
 class LLVMDoubleType() : LLVMType() {
 
-    override fun operatorMinus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression {
-        //TODO switch by types: int + double = int
-        return LLVMExpression(LLVMDoubleType(), "fsub double i32 $firstOp, $secondOp")
-    }
+    //TODO switch by types: int + double = int
+    override fun operatorMinus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression =
+            LLVMExpression(LLVMDoubleType(), "fsub double i32 $firstOp, $secondOp")
 
-    override fun operatorTimes(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression {
-        //TODO switch by types: int + double = int
-        return LLVMExpression(LLVMDoubleType(), "fmul double i32 $firstOp, $secondOp")
-    }
+    //TODO switch by types: int + double = int
+    override fun operatorTimes(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression =
+            LLVMExpression(LLVMDoubleType(), "fmul double i32 $firstOp, $secondOp")
 
-    override fun operatorPlus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression {
-        //TODO switch by types: int + double = int
-        return LLVMExpression(LLVMDoubleType(), "fadd double $firstOp, $secondOp")
-    }
+    //TODO switch by types: int + double = int
+    override fun operatorPlus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression =
+            LLVMExpression(LLVMDoubleType(), "fadd double $firstOp, $secondOp")
 
     override fun toString(): String {
         return "double"
diff --git a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMIntType.kt b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMIntType.kt
index ea7e59b4a6b..1f9e1e88ecb 100644
--- a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMIntType.kt
+++ b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMIntType.kt
@@ -6,23 +6,18 @@ import org.kotlinnative.translator.llvm.LLVMVariable
 
 class LLVMIntType() : LLVMType() {
 
-    override fun operatorMinus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression {
-        //TODO switch by types: int + double = int
-        return LLVMExpression(LLVMIntType(), "sub nsw i32 $firstOp, $secondOp")
-    }
+    //TODO switch by types: int + double = int
+    override fun operatorMinus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression =
+            LLVMExpression(LLVMIntType(), "sub nsw i32 $firstOp, $secondOp")
 
-    override fun operatorTimes(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression {
-        //TODO switch by types: int + double = int
-        return LLVMExpression(LLVMIntType(), "mul nsw i32 $firstOp, $secondOp")
-    }
+    //TODO switch by types: int + double = int
+    override fun operatorTimes(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression =
+            LLVMExpression(LLVMIntType(), "mul nsw i32 $firstOp, $secondOp")
 
-    override fun operatorPlus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression {
-        //TODO switch by types: int + double = int
-        return LLVMExpression(LLVMIntType(), "add nsw i32 $firstOp, $secondOp")
-    }
+    //TODO switch by types: int + double = int
+    override fun operatorPlus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression =
+            LLVMExpression(LLVMIntType(), "add nsw i32 $firstOp, $secondOp")
 
-    override fun toString(): String {
-        return "i32"
-    }
+    override fun toString() = "i32"
 
 }
\ No newline at end of file
diff --git a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMType.kt b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMType.kt
index af5e2634b70..4dac8131376 100644
--- a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMType.kt
+++ b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMType.kt
@@ -1,17 +1,19 @@
 package org.kotlinnative.translator.llvm.types;
 
 import org.kotlinnative.translator.exceptions.TranslationException
+import org.kotlinnative.translator.exceptions.UnimplementedException
 import org.kotlinnative.translator.llvm.LLVMExpression
 import org.kotlinnative.translator.llvm.LLVMVariable
 
 abstract class LLVMType() {
 
-    abstract fun operatorPlus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression;
-    abstract fun operatorTimes(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression;
-    abstract fun operatorMinus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression;
+    open fun operatorPlus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression = throw UnimplementedException()
+    open fun operatorTimes(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression = throw UnimplementedException()
+    open fun operatorMinus(result: LLVMVariable, firstOp: LLVMVariable, secondOp: LLVMVariable): LLVMExpression = throw UnimplementedException()
 }
 
-fun parseLLVMType(type: String): LLVMType = when(type) {
+fun parseLLVMType(type: String): LLVMType = when (type) {
     "i32" -> LLVMIntType()
+    "Unit" -> LLVMVoidType()
     else -> throw TranslationException()
 }
diff --git a/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMVoidType.kt b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMVoidType.kt
new file mode 100644
index 00000000000..d633fe75c2d
--- /dev/null
+++ b/translator/src/main/kotlin/org/kotlinnative/translator/llvm/types/LLVMVoidType.kt
@@ -0,0 +1,7 @@
+package org.kotlinnative.translator.llvm.types
+
+class LLVMVoidType() : LLVMType() {
+
+    override fun toString(): String = "void"
+
+}