diff --git a/schala-lang/language/src/ast.rs b/schala-lang/language/src/ast.rs
index 973389d..19e28d2 100644
--- a/schala-lang/language/src/ast.rs
+++ b/schala-lang/language/src/ast.rs
@@ -1,4 +1,7 @@
 use std::rc::Rc;
+use std::convert::From;
+
+use source_map::{SourceMap};
 
 use builtin::{BinOp, PrefixOp};
 
@@ -63,6 +66,12 @@ pub enum Variant {
 #[derive(Debug, PartialEq, Clone)]
 pub struct Expression(pub ExpressionType, pub Option<TypeIdentifier>);
 
+impl From<Expression> for SourceMap<Expression> {
+  fn from(node: Expression) -> Self {
+    SourceMap { node, data: None }
+  }
+}
+
 #[derive(Debug, PartialEq, Clone)]
 pub enum TypeIdentifier {
   Tuple(Vec<TypeIdentifier>),
@@ -116,6 +125,13 @@ pub enum ExpressionType {
   },
   ListLiteral(Vec<Expression>),
 }
+
+impl From<ExpressionType> for SourceMap<ExpressionType> {
+  fn from(node: ExpressionType) -> Self {
+    SourceMap { node, data: None }
+  }
+}
+
 #[derive(Debug, PartialEq, Clone)]
 pub enum Discriminator {
   Simple(Expression),