diff --git a/schala-lang/language/src/lib.rs b/schala-lang/language/src/lib.rs
index 5dbfaa1..5e4de2c 100644
--- a/schala-lang/language/src/lib.rs
+++ b/schala-lang/language/src/lib.rs
@@ -19,6 +19,7 @@ extern crate ena;
 
 use stopwatch::Stopwatch;
 
+use std::time::Duration;
 use std::cell::RefCell;
 use std::rc::Rc;
 use std::collections::HashSet;
@@ -234,12 +235,13 @@ impl SourceReference {
   }
 }
 
+#[derive(Default)]
 struct PassDebugArtifact {
-  artifact: Option<String>
+  artifacts: Vec<String>
 }
 impl PassDebugArtifact {
   fn add_artifact(&mut self, artifact: String) {
-    self.artifact = Some(artifact)
+    self.artifacts.push(artifact)
   }
 }
 
@@ -254,55 +256,46 @@ fn stage_names() -> Vec<&'static str> {
   ]
 }
 
+
 impl ProgrammingLanguageInterface for Schala {
   fn get_language_name(&self) -> String { format!("Schala") }
   fn get_source_file_suffix(&self) -> String { format!("schala") }
 
   fn run_computation(&mut self, request: ComputationRequest) -> ComputationResponse {
     let ComputationRequest { source, debug_requests } = request;
-    let stage_names = stage_names();
     self.source_reference.load_new_source(source);
 
+    fn output_wrapper<Input, Output, F>(
+      n: usize,
+      func: F,
+      input: Input,
+      schala: &mut Schala,
+      stage_durations: &mut Vec<(String, Duration)>,
+      sw: &Stopwatch,
+      debug_requests: &HashSet<DebugAsk>) -> Result<Output, String>
+      where F: Fn(Input, &mut Schala, Option<&mut PassDebugArtifact>) -> Result<Output, String>,
+    {
+      let stage_names = stage_names();
+      let mut debug_artifact = if debug_requests.contains(&DebugAsk::ByStage { stage_name: stage_names[n].to_string() }) {
+        Some(PassDebugArtifact::default())
+      } else {
+        None
+      };
+      let output = func(input, schala, debug_artifact.as_mut());
+      stage_durations.push((stage_names[n].to_string(), sw.elapsed()));
+      output
+    }
+
     let sw = Stopwatch::start_new();
     let mut stage_durations = Vec::new();
 
-    let main_output: Result<String, String> = {
-      let n = 0;
-      let debug_artifact = None;
-      let output = tokenizing(source, self, debug_artifact);
-      stage_durations.push((stage_names[n].to_string(), sw.elapsed()));
-      output
-    }.and_then(|tokens| {
-      let n = 1;
-      let debug_artifact = None;
-      let output = parsing(tokens, self, debug_artifact);
-      stage_durations.push((stage_names[n].to_string(), sw.elapsed()));
-      output
-    }).and_then(|ast| {
-      let n = 2;
-      let debug_artifact = None;
-      let output = symbol_table(ast, self, debug_artifact);
-      stage_durations.push((stage_names[n].to_string(), sw.elapsed()));
-      output
-    }).and_then(|ast| {
-      let n = 3;
-      let debug_artifact = None;
-      let output = typechecking(ast, self, debug_artifact);
-      stage_durations.push((stage_names[n].to_string(), sw.elapsed()));
-      output
-    }).and_then(|ast| {
-      let n = 4;
-      let debug_artifact = None;
-      let output = ast_reducing(ast, self, debug_artifact);
-      stage_durations.push((stage_names[n].to_string(), sw.elapsed()));
-      output
-    }).and_then(|reduced_ast| {
-      let n = 5;
-      let debug_artifact = None;
-      let output = eval(reduced_ast, self, debug_artifact);
-      stage_durations.push((stage_names[n].to_string(), sw.elapsed()));
-      output
-    });
+    let main_output: Result<String, String> = Ok(source)
+      .and_then(|source| output_wrapper(0, tokenizing, source, self, &mut stage_durations, &sw, &debug_requests))
+      .and_then(|tokens| output_wrapper(1, parsing, tokens, self, &mut stage_durations, &sw, &debug_requests))
+      .and_then(|ast| output_wrapper(2, symbol_table, ast, self, &mut stage_durations, &sw, &debug_requests))
+      .and_then(|ast| output_wrapper(3, typechecking, ast, self, &mut stage_durations, &sw, &debug_requests))
+      .and_then(|ast| output_wrapper(4, ast_reducing, ast, self, &mut stage_durations, &sw, &debug_requests))
+      .and_then(|reduced_ast| output_wrapper(5, eval, reduced_ast, self, &mut stage_durations, &sw, &debug_requests));
 
     let total_duration = sw.elapsed();
     let global_output_stats = GlobalOutputStats {