diff --git a/schala-lib/src/language.rs b/schala-lib/src/language.rs
index 6e84f03..6c9e531 100644
--- a/schala-lib/src/language.rs
+++ b/schala-lib/src/language.rs
@@ -75,6 +75,15 @@ impl UnfinishedComputation {
   }
 }
 
+impl FinishedComputation {
+  pub fn to_string(&self) -> String {
+    match self.text_output {
+      Ok(ref s) => s.clone(),
+      Err(ref s) => format!("Error: {}", s)
+    }
+  }
+}
+
 /*
 //TODO I'll probably wanna implement this later
 #[derive(Debug)]
@@ -115,10 +124,16 @@ impl TraceArtifact {
 }
 
 pub trait ProgrammingLanguageInterface {
-  fn evaluate_in_repl(&mut self, input: &str, eval_options: &EvalOptions) -> LanguageOutput;
+  fn evaluate_in_repl(&mut self, input: &str, eval_options: &EvalOptions) -> LanguageOutput {
+    LanguageOutput { output: format!("Defunct"), artifacts: vec![], failed: false }
+  }
   fn evaluate_noninteractive(&mut self, input: &str, eval_options: &EvalOptions) -> LanguageOutput {
     self.evaluate_in_repl(input, eval_options)
   }
+
+  fn repl_evaluate(&mut self, input: &str, eval_options: &EvalOptions) -> FinishedComputation {
+    FinishedComputation { artifacts: HashMap::new(), text_output: Err(format!("REPL evaluation not implemented")) }
+  }
   fn get_language_name(&self) -> String;
   fn get_source_file_suffix(&self) -> String;
   fn compile(&mut self, _input: &str) -> LLVMCodeString {
diff --git a/schala-lib/src/lib.rs b/schala-lib/src/lib.rs
index 899822a..f41436b 100644
--- a/schala-lib/src/lib.rs
+++ b/schala-lib/src/lib.rs
@@ -32,7 +32,7 @@ pub mod llvm_wrap;
 
 include!(concat!(env!("OUT_DIR"), "/static.rs"));
 
-pub use language::{ProgrammingLanguageInterface, EvalOptions, TraceArtifact, LanguageOutput, LLVMCodeString};
+pub use language::{ProgrammingLanguageInterface, EvalOptions, TraceArtifact, LanguageOutput, LLVMCodeString, FinishedComputation, UnfinishedComputation};
 pub type PLIGenerator = Box<Fn() -> Box<ProgrammingLanguageInterface> + Send + Sync>;
 
 pub fn schala_main(generators: Vec<PLIGenerator>) {
@@ -198,7 +198,7 @@ impl Repl {
 
   fn input_handler(&mut self, input: &str) -> String {
     let ref mut language = self.languages[self.current_language_index];
-    let interpreter_output = language.evaluate_in_repl(input, &self.options);
+    let interpreter_output = language.repl_evaluate(input, &self.options);
     interpreter_output.to_string()
   }
 
diff --git a/src/schala_lang/mod.rs b/src/schala_lang/mod.rs
index bdaa70a..0392559 100644
--- a/src/schala_lang/mod.rs
+++ b/src/schala_lang/mod.rs
@@ -1,5 +1,5 @@
 use itertools::Itertools;
-use schala_lib::{ProgrammingLanguageInterface, EvalOptions, TraceArtifact, LanguageOutput};
+use schala_lib::{ProgrammingLanguageInterface, EvalOptions, TraceArtifact, LanguageOutput, UnfinishedComputation, FinishedComputation};
 
 macro_rules! bx {
   ($e:expr) => { Box::new($e) }
@@ -12,6 +12,7 @@ mod parsing;
 mod typechecking;
 mod eval;
 
+
 use self::typechecking::{TypeContext};
 
 pub struct Schala {
@@ -37,68 +38,54 @@ impl ProgrammingLanguageInterface for Schala {
     format!("schala")
   }
 
-  fn evaluate_in_repl(&mut self, input: &str, options: &EvalOptions) -> LanguageOutput {
-    let mut output = LanguageOutput::default();
+  fn repl_evaluate(&mut self, input: &str, options: &EvalOptions) -> FinishedComputation {
+    let mut evaluation = UnfinishedComputation::default();
+
+    //tokenzing
     let tokens = tokenizing::tokenize(input);
-    if options.debug_tokens {
-      let token_string = tokens.iter().map(|t| format!("{:?}<L:{},C:{}>", t.token_type, t.offset.0, t.offset.1)).join(", ");
-      output.add_artifact(TraceArtifact::new("tokens", format!("{:?}", token_string)));
-    }
+    let token_string = tokens.iter().map(|t| format!("{:?}<L:{},C:{}>", t.token_type, t.offset.0, t.offset.1)).join(", ");
+    evaluation.add_artifact(TraceArtifact::new("tokens", token_string));
 
     {
       let token_errors: Vec<&String> = tokens.iter().filter_map(|t| t.get_error()).collect();
       if token_errors.len() != 0 {
-        output.add_output(format!("Tokenization error: {:?}\n", token_errors));
-        output.failed = true;
-        return output;
+        return evaluation.output(Err(format!("Tokenization error: {:?}\n", token_errors)));
       }
     }
 
+    // parsing
     let ast = match parsing::parse(tokens) {
       (Ok(ast), trace) => {
-        if options.debug_parse {
-          output.add_artifact(TraceArtifact::new_parse_trace(trace));
-          output.add_artifact(TraceArtifact::new("ast", format!("{:?}", ast)));
-        }
+        evaluation.add_artifact(TraceArtifact::new_parse_trace(trace));
+        evaluation.add_artifact(TraceArtifact::new("ast", format!("{:?}", ast)));
         ast
       },
       (Err(err), trace) => {
-        output.add_artifact(TraceArtifact::new_parse_trace(trace));
-        output.add_output(format!("Parse error: {:?}\n", err.msg));
-        output.failed = true;
-        return output;
+        evaluation.add_artifact(TraceArtifact::new_parse_trace(trace));
+        return evaluation.output(Err(format!("Parse error: {:?}\n", err.msg)));
       }
     };
 
+
+    //symbol table
     match self.type_context.add_top_level_types(&ast) {
       Ok(()) => (),
       Err(msg) => {
-        output.add_artifact(TraceArtifact::new("type_check", msg));
-        //return output
+        evaluation.add_artifact(TraceArtifact::new("type_check", msg));
       }
     };
 
-    if options.debug_symbol_table {
-      let text = self.type_context.debug_symbol_table();
-      output.add_artifact(TraceArtifact::new("symbol_table", text));
-    }
-
+    //typechecking
     match self.type_context.type_check_ast(&ast) {
-      Ok(ty) => {
-        output.add_artifact(TraceArtifact::new("type_check", format!("{:?}", ty)));
-      },
-      Err(msg) => {
-        output.add_artifact(TraceArtifact::new("type_check", msg));
-        /*
-        output.add_output(format!("Type error"));
-        return output;
-        */
-      }
-    }
+      Ok(ty) => evaluation.add_artifact(TraceArtifact::new("type_check", format!("{:?}", ty))),
+      Err(msg) => evaluation.add_artifact(TraceArtifact::new("type_check", msg)),
+    };
+
+    let text = self.type_context.debug_symbol_table();
+    evaluation.add_artifact(TraceArtifact::new("symbol_table", text));
 
     let evaluation_outputs = self.state.evaluate(ast);
     let text_output: String = evaluation_outputs.into_iter().intersperse(format!("\n")).collect();
-    output.add_output(text_output);
-    return output;
+    evaluation.output(Ok(text_output))
   }
 }