diff --git a/schala-lang/language/src/lib.rs b/schala-lang/language/src/lib.rs
index f986e21..8b82cb8 100644
--- a/schala-lang/language/src/lib.rs
+++ b/schala-lang/language/src/lib.rs
@@ -80,7 +80,7 @@ impl Schala {
     let prelude = include_str!("prelude.schala");
     let mut s = Schala::new_blank_env();
 
-    let request = ComputationRequest { source: prelude.to_string(), debug_requests: vec![] };
+    let request = ComputationRequest { source: prelude, debug_requests: vec![] };
     s.run_computation(request);
     s
   }
diff --git a/schala-repl/src/language.rs b/schala-repl/src/language.rs
index 2433699..989c3e5 100644
--- a/schala-repl/src/language.rs
+++ b/schala-repl/src/language.rs
@@ -17,9 +17,8 @@ pub trait ProgrammingLanguageInterface {
   }
 }
 
-//TODO source can probably be a &str
-pub struct ComputationRequest {
-  pub source: String,
+pub struct ComputationRequest<'a> {
+  pub source: &'a str,
   pub debug_requests: Vec<DebugRequest>,
 }
 
diff --git a/schala-repl/src/repl/mod.rs b/schala-repl/src/repl/mod.rs
index 38bf025..1f04063 100644
--- a/schala-repl/src/repl/mod.rs
+++ b/schala-repl/src/repl/mod.rs
@@ -175,7 +175,7 @@ impl Repl {
     let ref mut language_state = self.get_cur_language_state();
 
     let request = ComputationRequest {
-      source: input.to_string(),
+      source: input,
       debug_requests: vec![],
     };