Split blocks and closures (#7075)

* Split closures and blocks

* Tests mostly working

* finish last fixes, passes all tests

* fmt

crates/nu-cli/src/prompt_update.rs

@@ -29,7 +29,7 @@ fn get_prompt_string(
     stack
         .get_env_var(engine_state, prompt)
         .and_then(|v| match v {
-            Value::Block {
+            Value::Closure {
                 val: block_id,
                 captures,
                 ..
@@ -59,6 +59,31 @@ fn get_prompt_string(
                     }
                 }
             }
+            Value::Block { val: block_id, .. } => {
+                let block = engine_state.get_block(block_id);
+                // Use eval_subexpression to force a redirection of output, so we can use everything in prompt
+                let ret_val = eval_subexpression(
+                    engine_state,
+                    stack,
+                    block,
+                    PipelineData::new(Span::new(0, 0)), // Don't try this at home, 0 span is ignored
+                );
+                info!(
+                    "get_prompt_string (block) {}:{}:{}",
+                    file!(),
+                    line!(),
+                    column!()
+                );
+
+                match ret_val {
+                    Ok(ret_val) => Some(ret_val),
+                    Err(err) => {
+                        let working_set = StateWorkingSet::new(engine_state);
+                        report_error(&working_set, &err);
+                        None
+                    }
+                }
+            }
             Value::String { .. } => Some(PipelineData::Value(v.clone(), None)),
             _ => None,
         })