From ee87695626d39cbbb593d411226cb18511ac656f Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Tue, 30 Jul 2019 01:33:09 -0700
Subject: [PATCH] Simplify Alternative data structure

Most of the subfields are duplicated on Subpattern so just use that
directly
---
 schala-lang/language/src/eval.rs        | 14 +++++++-------
 schala-lang/language/src/reduced_ast.rs | 25 +++++++++++++------------
 2 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/schala-lang/language/src/eval.rs b/schala-lang/language/src/eval.rs
index 9f6b7d8..a27d693 100644
--- a/schala-lang/language/src/eval.rs
+++ b/schala-lang/language/src/eval.rs
@@ -425,15 +425,15 @@ impl<'a> State<'a> {
     let cond = self.expression(Node::Expr(cond))?;
     for alt in alternatives {
       // no matter what type of condition we have, ignore alternative if the guard evaluates false
-      if !self.guard_passes(&alt.guard, &cond)? {
+      if !self.guard_passes(&alt.matchable.guard, &cond)? {
         continue;
       }
 
       match cond {
         Node::PrimObject { ref tag, ref items, .. } => {
-          if alt.tag.map(|t| t == *tag).unwrap_or(true) {
-            let mut inner_state = self.new_frame(items, &alt.bound_vars);
-            if all_subpatterns_pass(&mut inner_state, &alt.subpatterns, items)? {
+          if alt.matchable.tag.map(|t| t == *tag).unwrap_or(true) {
+            let mut inner_state = self.new_frame(items, &alt.matchable.bound_vars);
+            if all_subpatterns_pass(&mut inner_state, &alt.matchable.subpatterns, items)? {
               return inner_state.block(alt.item);
             } else {
               continue;
@@ -441,15 +441,15 @@ impl<'a> State<'a> {
           }
         },
         Node::PrimTuple { ref items } =>  {
-          let mut inner_state = self.new_frame(items, &alt.bound_vars);
-          if all_subpatterns_pass(&mut inner_state, &alt.subpatterns, items)? {
+          let mut inner_state = self.new_frame(items, &alt.matchable.bound_vars);
+          if all_subpatterns_pass(&mut inner_state, &alt.matchable.subpatterns, items)? {
             return inner_state.block(alt.item);
           } else {
             continue;
           }
         },
         Node::Expr(ref _e) => {
-          if let None = alt.tag {
+          if let None = alt.matchable.tag {
             return self.block(alt.item)
           }
         }
diff --git a/schala-lang/language/src/reduced_ast.rs b/schala-lang/language/src/reduced_ast.rs
index 695d771..de228b5 100644
--- a/schala-lang/language/src/reduced_ast.rs
+++ b/schala-lang/language/src/reduced_ast.rs
@@ -60,10 +60,7 @@ pub type BoundVars = Vec<Option<Rc<String>>>; //remember that order matters here
 
 #[derive(Debug, Clone)]
 pub struct Alternative {
-  pub tag: Option<usize>,
-  pub subpatterns: Vec<Option<Subpattern>>,
-  pub guard: Option<Expr>,
-  pub bound_vars: BoundVars,
+  pub matchable: Subpattern,
   pub item: Vec<Stmt>,
 }
 
@@ -201,10 +198,12 @@ fn reduce_if_expression(discriminator: &Discriminator, body: &IfExpressionBody,
       let alternatives = vec![
         pat.to_alternative(then_clause, symbol_table),
         Alternative {
-          tag: None,
-          subpatterns: vec![],
-          bound_vars: vec![],
-          guard: None,
+          matchable: Subpattern {
+            tag: None,
+            subpatterns: vec![],
+            bound_vars: vec![],
+            guard: None,
+          },
           item: else_clause
         },
       ];
@@ -278,10 +277,12 @@ impl Pattern {
   fn to_alternative(&self, item: Vec<Stmt>, symbol_table: &SymbolTable) -> Alternative {
     let s = self.to_subpattern(symbol_table);
     Alternative {
-      tag: s.tag,
-      subpatterns: s.subpatterns,
-      bound_vars: s.bound_vars,
-      guard: s.guard,
+      matchable: Subpattern {
+        tag: s.tag,
+        subpatterns: s.subpatterns,
+        bound_vars: s.bound_vars,
+        guard: s.guard,
+      },
       item
     }
   }