Pattern-matching in reduced AST

schala-lang/src/reduced_ast.rs

@@ -1,6 +1,6 @@
 use std::rc::Rc;
 
-use ast::{AST, Statement, Expression, Declaration, Discriminator, IfExpressionBody};
+use ast::{AST, Statement, Expression, Declaration, Discriminator, IfExpressionBody, Pattern};
 use symbol_table::{Symbol, SymbolSpec, SymbolTable};
 use builtin::{BinOp, PrefixOp};
 
@@ -45,6 +45,10 @@ pub enum Expr {
     then_clause: Vec<Stmt>,
     else_clause: Vec<Stmt>,
   },
+  Match {
+    cond: Box<Expr>,
+    arms: Vec<(Pattern, Vec<Stmt>)>
+  },
   UnimplementedSigilValue
 }
 
@@ -112,12 +116,18 @@ impl Expression {
         args: arguments.iter().map(|arg| arg.reduce(symbol_table)).collect(),
       },
       TupleLiteral(exprs) => Expr::Tuple(exprs.iter().map(|e| e.reduce(symbol_table)).collect()),
-      IfExpression { discriminator, body } => {
-        let cond = Box::new(match **discriminator {
+      IfExpression { discriminator, body } => reduce_if_expression(discriminator, body, symbol_table),
+      _ => Expr::UnimplementedSigilValue,
+    }
+  }
+}
+
+fn reduce_if_expression(discriminator: &Discriminator, body: &IfExpressionBody, symbol_table: &SymbolTable) -> Expr {
+  let cond = Box::new(match *discriminator {
     Discriminator::Simple(ref expr) => expr.reduce(symbol_table),
     _ => panic!(),
   });
-        match **body {
+  match *body {
     IfExpressionBody::SimpleConditional(ref then_clause, ref else_clause) => {
       let then_clause = then_clause.iter().map(|expr| expr.reduce(symbol_table)).collect();
       let else_clause = match else_clause {
@@ -136,10 +146,6 @@ impl Expression {
     },
     _ => panic!(),
   }
-      },
-      _ => Expr::UnimplementedSigilValue,
-    }
-  }
 }
 
 impl Declaration {