From abe2db25b2104f13432b150be36fc898f69cce32 Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Mon, 15 Oct 2018 19:54:17 -0700
Subject: [PATCH] full if matching working with basic patterns

---
 schala-lang/src/eval.rs        | 19 ++++++++++++++-
 schala-lang/src/reduced_ast.rs | 44 +++++++++++++++++++++-------------
 2 files changed, 45 insertions(+), 18 deletions(-)

diff --git a/schala-lang/src/eval.rs b/schala-lang/src/eval.rs
index 8315ed9..42880aa 100644
--- a/schala-lang/src/eval.rs
+++ b/schala-lang/src/eval.rs
@@ -468,7 +468,7 @@ mod eval_tests {
   }
 
   #[test]
-  fn basic_patterns() {
+  fn if_is_patterns() {
     let source = r#"
 type Option<T> = Some(T) | None
 let x = Some(9); if x is Some(q) then { q } else { 0 }"#;
@@ -479,4 +479,21 @@ type Option<T> = Some(T) | None
 let x = None; if x is Some(q) then { q } else { 0 }"#;
     fresh_env!(source, "0");
   }
+
+  #[test]
+  fn full_if_matching() {
+    let source = r#"
+type Option<T> = Some(T) | None
+let a = None
+if a { is None -> 4, is Some(x) -> x }
+"#;
+  fresh_env!(source, "4");
+
+    let source = r#"
+type Option<T> = Some(T) | None
+let a = Some(99)
+if a { is None -> 4, is Some(x) -> x }
+"#;
+  fresh_env!(source, "99");
+  }
 }
diff --git a/schala-lang/src/reduced_ast.rs b/schala-lang/src/reduced_ast.rs
index 3eb7bf2..96a46eb 100644
--- a/schala-lang/src/reduced_ast.rs
+++ b/schala-lang/src/reduced_ast.rs
@@ -189,24 +189,29 @@ fn reduce_if_expression(discriminator: &Discriminator, body: &IfExpressionBody,
 impl Pattern {
   fn to_alternative(&self, item: Vec<Stmt>, symbol_table: &SymbolTable) -> Alternative {
     use self::Pattern::*;
+
+    fn handle_symbol(symbol: &Symbol, subpatterns: &Vec<Pattern>, item: Vec<Stmt>) -> Alternative {
+      let tag = match symbol.spec {
+        SymbolSpec::DataConstructor { index, .. } => index.clone(),
+        _ => panic!("Symbol is not a data constructor - this should've been caught in type-checking"),
+      };
+      let bound_vars = subpatterns.iter().map(|p| match p {
+        Literal(PatternLiteral::VarPattern(var)) => Some(var.clone()),
+        Ignored => None,
+        _ => None,
+      }).collect();
+      Alternative {
+        tag: Some(tag),
+        guard: None,
+        bound_vars,
+        item,
+      }
+    }
+
     match self {
       TupleStruct(name, subpatterns) => {
-        let symbol = symbol_table.values.get(name).expect(&format!("Symbol {} not found", name));
-        let tag = match symbol.spec {
-          SymbolSpec::DataConstructor { index, .. } => index.clone(),
-          _ => panic!("Bad symbol"),
-        };
-        let bound_vars = subpatterns.iter().map(|p| match p {
-          Literal(PatternLiteral::VarPattern(var)) => Some(var.clone()),
-          Ignored => None,
-          _ => None,
-        }).collect();
-        Alternative {
-          tag: Some(tag),
-          guard: None,
-          bound_vars,
-          item,
-        }
+        let symbol = symbol_table.lookup_by_name(name).expect(&format!("Symbol {} not found", name));
+        handle_symbol(symbol, subpatterns, item)
       },
       TuplePattern(_items) => {
         unimplemented!()
@@ -219,7 +224,12 @@ impl Pattern {
         PatternLiteral::NumPattern { neg, num } => unimplemented!(),
         PatternLiteral::StringPattern(_s) => unimplemented!(),
         PatternLiteral::BoolPattern(_b) => unimplemented!(),
-        PatternLiteral::VarPattern(_var) => unimplemented!(),
+        PatternLiteral::VarPattern(var) => match symbol_table.lookup_by_name(var) {
+          Some(symbol) => handle_symbol(symbol, &vec![], item),
+          None => {
+            unimplemented!()
+          }
+        }
       },
     }
   }