full if matching working with basic patterns

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");
+  }
 }

schala-lang/src/reduced_ast.rs

@@ -189,12 +189,11 @@ fn reduce_if_expression(discriminator: &Discriminator, body: &IfExpressionBody,
 impl Pattern {
   fn to_alternative(&self, item: Vec<Stmt>, symbol_table: &SymbolTable) -> Alternative {
     use self::Pattern::*;
-    match self {
-      TupleStruct(name, subpatterns) => {
-        let symbol = symbol_table.values.get(name).expect(&format!("Symbol {} not found", name));
+
+    fn handle_symbol(symbol: &Symbol, subpatterns: &Vec<Pattern>, item: Vec<Stmt>) -> Alternative {
       let tag = match symbol.spec {
         SymbolSpec::DataConstructor { index, .. } => index.clone(),
-          _ => panic!("Bad symbol"),
+        _ => 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()),
@@ -207,6 +206,12 @@ impl Pattern {
         bound_vars,
         item,
       }
+    }
+
+    match self {
+      TupleStruct(name, subpatterns) => {
+        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!()
+          }
+        }
       },
     }
   }