From 37070a6b3e576fbe05cf002f39fe52bf429f7757 Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Sat, 20 Oct 2018 18:00:05 -0700
Subject: [PATCH] Move pass chain generation from macro to codegen

---
 schala-lang/language/src/lib.rs |  1 -
 schala-repl-codegen/src/lib.rs  | 62 ++++++++++++++++++++++++++++++---
 schala-repl/src/language.rs     | 58 ------------------------------
 3 files changed, 57 insertions(+), 64 deletions(-)

diff --git a/schala-lang/language/src/lib.rs b/schala-lang/language/src/lib.rs
index 12632f0..ae71054 100644
--- a/schala-lang/language/src/lib.rs
+++ b/schala-lang/language/src/lib.rs
@@ -7,7 +7,6 @@ extern crate itertools;
 extern crate lazy_static;
 #[macro_use]
 extern crate maplit;
-#[macro_use]
 extern crate schala_repl;
 #[macro_use]
 extern crate schala_repl_codegen;
diff --git a/schala-repl-codegen/src/lib.rs b/schala-repl-codegen/src/lib.rs
index ce2cad3..6016783 100644
--- a/schala-repl-codegen/src/lib.rs
+++ b/schala-repl-codegen/src/lib.rs
@@ -1,4 +1,5 @@
 #![feature(trace_macros)]
+#![recursion_limit="128"]
 extern crate proc_macro;
 extern crate proc_macro2;
 #[macro_use]
@@ -66,10 +67,62 @@ fn get_attribute_identifier(attr_name: &str, attrs: &Vec<Attribute>) -> Option<p
   })
 }
 
-fn pass_chain_new(idents: Vec<Ident>) -> proc_macro2::TokenStream {
+/* a pass_chain function signature looks like:
+ * fn(&mut ProgrammingLanguageInterface, A, Option<&mut DebugHandler>) -> Result<B, String>
+ *
+ * TODO use some kind of failure-handling library to make this better
+ */
+fn generate_pass_chain(idents: Vec<Ident>) -> proc_macro2::TokenStream {
+  let final_return = quote! {
+    {
+      let final_output: FinishedComputation = unfinished_computation.finish(Ok(input_to_next_stage));
+      final_output
+    }
+  };
+
+  let nested_passes = idents.iter()
+    .rev()
+    .fold(final_return, |later_fragment, pass_name| {
+      quote! {
+        {
+          let pass_name = stringify!(#pass_name);
+          let (output, duration) = {
+            let ref debug_map = eval_options.debug_passes;
+            let debug_handle = match debug_map.get(pass_name) {
+              Some(PassDebugOptionsDescriptor { opts }) => {
+                let ptr = &mut unfinished_computation;
+                ptr.cur_debug_options = opts.clone();
+                Some(ptr)
+              }
+              _ => None
+            };
+            let start = time::Instant::now();
+            let pass_output = #pass_name(self, input_to_next_stage, debug_handle);
+            let elapsed = start.elapsed();
+            (pass_output, elapsed)
+          };
+          if eval_options.debug_timing {
+            unfinished_computation.durations.push(duration);
+          }
+          match output {
+            Ok(input_to_next_stage) => #later_fragment,
+            //TODO this error type needs to be guaranteed to provide a useable string
+            Err(err) => return unfinished_computation.output(Err(format!("Pass {} failed:\n{}", pass_name, err))),
+          }
+        }
+      }
+    });
+
   quote! {
-    let mut chain = pass_chain![self, options; #(#idents),* ];
-    chain(input)
+    {
+      use std::time;
+      use schala_repl::PassDebugOptionsDescriptor;
+
+      let eval_options = options;
+      let input_to_next_stage = input;
+      let mut unfinished_computation = UnfinishedComputation::default();
+      #nested_passes
+    }
   }
 }
 
@@ -119,7 +172,7 @@ pub fn derive_programming_language_interface(input: TokenStream) -> TokenStream
     }
   });
 
-  let pass_chain = pass_chain_new(pass_idents.collect());
+  let pass_chain = generate_pass_chain(pass_idents.collect());
 
   let tokens = quote! {
     use schala_repl::PassDescriptor;
@@ -131,7 +184,6 @@ pub fn derive_programming_language_interface(input: TokenStream) -> TokenStream
         #file_ext.to_string()
       }
       fn execute_pipeline(&mut self, input: &str, options: &EvalOptions) -> FinishedComputation {
-
         #pass_chain
       }
       fn get_passes(&self) -> Vec<PassDescriptor> {
diff --git a/schala-repl/src/language.rs b/schala-repl/src/language.rs
index 29c04ff..6c389e8 100644
--- a/schala-repl/src/language.rs
+++ b/schala-repl/src/language.rs
@@ -173,61 +173,3 @@ pub trait ProgrammingLanguageInterface {
     None
   }
 }
-
-/* a pass_chain function signature looks like: 
- * fn(&mut ProgrammingLanguageInterface, A, Option<&mut DebugHandler>) -> Result<B, String>
- *
- * TODO use some kind of failure-handling library to make this better
- */
-
-#[macro_export]
-macro_rules! pass_chain {
-  ($state:expr, $eval_options:expr; $($pass:path), *) => {
-    |text_input| {
-      let mut comp = UnfinishedComputation::default();
-      pass_chain_helper! { ($state, comp, $eval_options); text_input $(, $pass)* }
-    }
-  };
-}
-
-#[macro_export]
-macro_rules! pass_chain_helper {
-  (($state:expr, $comp:expr, $eval_options:expr); $input:expr, $pass:path $(, $rest:path)*) => {
-    {
-      use std::time;
-      use schala_repl::PassDebugOptionsDescriptor;
-      let pass_name = stringify!($pass);
-      let (output, duration) = {
-        let ref debug_map = $eval_options.debug_passes;
-        let debug_handle = match debug_map.get(pass_name) {
-          Some(PassDebugOptionsDescriptor { opts }) => {
-            let ptr = &mut $comp;
-            ptr.cur_debug_options = opts.clone();
-            Some(ptr)
-          }
-          _ => None
-        };
-        let start = time::Instant::now();
-        let pass_output = $pass($state, $input, debug_handle);
-        let elapsed = start.elapsed();
-        (pass_output, elapsed)
-      };
-      if $eval_options.debug_timing {
-        $comp.durations.push(duration);
-      }
-      match output {
-        Ok(result) => pass_chain_helper! { ($state, $comp, $eval_options); result $(, $rest)* },
-        Err(err) => { //TODO this error type needs to be guaranteed to provide a useable string
-          $comp.output(Err(format!("Pass {} failed:\n{}", pass_name, err)))
-        }
-      }
-    }
-  };
-  // Done
-  (($state:expr, $comp:expr, $eval_options:expr); $final_output:expr) => {
-    {
-      let final_output: FinishedComputation = $comp.finish(Ok($final_output));
-      final_output
-    }
-  };
-}