Show err output when evaluating non-interactively

schala-lang/src/eval.rs

@@ -102,17 +102,17 @@ impl<'a> State<'a> {
     State { parent_frame: Some(parent), values: HashMap::new() }
   }
 
-  pub fn evaluate(&mut self, ast: AST) -> Vec<String> {
+  pub fn evaluate(&mut self, ast: AST) -> Vec<Result<String, String>> {
     let mut acc = vec![];
     for statement in ast.0 {
       match self.eval_statement(statement) {
         Ok(output) => {
           if let Some(fully_evaluated) = output {
-            acc.push(fully_evaluated.to_string());
+            acc.push(Ok(fully_evaluated.to_string()));
           }
         },
         Err(error) => {
-          acc.push(format!("Eval error: {}", error));
+          acc.push(Err(format!("Eval error: {}", error)));
           return acc;
         },
       }

schala-lang/src/lib.rs

@@ -107,7 +107,12 @@ impl ProgrammingLanguageInterface for Schala {
     }
 
     let evaluation_outputs = self.state.evaluate(ast);
-    let text_output: String = evaluation_outputs.into_iter().intersperse(format!("\n")).collect();
+    let text_output: Result<Vec<String>, String> = evaluation_outputs
-    evaluation.output(Ok(text_output))
+      .into_iter()
+      .collect();
+
+    let eval_output = text_output
+      .map(|v| { v.into_iter().intersperse(format!("\n")).collect() });
+    evaluation.output(eval_output)
   }
 }

source_files/schala/first.schala

@@ -4,6 +4,9 @@ fn main() {
   a + b
 }
 
+foo
+
 print(main())
 
 
+