From fd89de77cc2bfc75c26081f0092fee02f0abe183 Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Sun, 29 Apr 2018 00:55:39 -0700
Subject: [PATCH] Making pipeline macro nicer

---
 schala-lang/src/lib.rs      |  4 +---
 schala-repl/src/language.rs | 34 +++++++++++++++++++++-------------
 2 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/schala-lang/src/lib.rs b/schala-lang/src/lib.rs
index 23083fe..a497974 100644
--- a/schala-lang/src/lib.rs
+++ b/schala-lang/src/lib.rs
@@ -60,9 +60,7 @@ impl ProgrammingLanguageInterface for Schala {
   fn execute_pipeline(&mut self, input: &str, options: &EvalOptions) -> FinishedComputation {
     //let chain = pass_chain![tokenizing::tokenize, parsing::parse];
     let chain = pass_chain![tokenizing_stage, parsing_stage];
-    let output = Ok(format!("{:?}", chain(input)));
-    let mut evaluation = UnfinishedComputation::default();
-    evaluation.output(output) //TODO rename this method it's confusing
+    chain(input)
   }
 
   fn execute(&mut self, input: &str, options: &EvalOptions) -> FinishedComputation {
diff --git a/schala-repl/src/language.rs b/schala-repl/src/language.rs
index 8fde299..74b81b3 100644
--- a/schala-repl/src/language.rs
+++ b/schala-repl/src/language.rs
@@ -183,26 +183,34 @@ pub trait ProgrammingLanguageInterface {
 #[macro_export]
 macro_rules! pass_chain {
   ($($pass:path), *) => {
-    |begin| pass_chain_helper! { begin $(, $pass)* }
+    |text_input| { pass_chain_helper! { text_input $(, $pass)* } }
   };
 }
 
+//generates a function resulting in (for now) the return type of the last one
+//but should in the future return a FinishedComputation
 #[macro_export]
 macro_rules! pass_chain_helper {
-  ($e:expr, $next:path $(, $rest:path)*) => {
-    pass_chain_helper! {
-      {
-        let output = $next({
-          let input = $e;
-          println!("About to run: {}", stringify!($next));
-          input
-        });
-        println!("Finished running {}", stringify!($next));
-        output.unwrap()
+  ($input:expr, $pass:path $(, $rest:path)*) => {
+    {
+      let pass_name = stringify!($pass);
+      println!("Running pass {}", pass_name);
+      let output = $pass($input);
+      match output {
+        Ok(result) => pass_chain_helper! { result $(, $rest)* },
+        Err(err) => {
+          let comp = UnfinishedComputation::default();
+          comp.output(Err(format!("Pass {} failed with {:?}", pass_name, err)))
+        }
       }
-      $(, $rest)*
     }
   };
   // Done
-  ($e:expr) => { $e };
+  ($final_output:expr) => {
+    {
+      let comp = UnfinishedComputation::default();
+      let final_output: FinishedComputation = comp.output(Ok(format!("{:?}", $final_output)));
+      final_output
+    }
+  };
 }