--- a/ast/Exp.d	Mon Apr 28 21:47:01 2008 +0200
+++ b/ast/Exp.d	Mon Apr 28 21:51:39 2008 +0200
@@ -8,7 +8,8 @@
 
 import lexer.Token;
 
-import sema.SymbolTable;
+import sema.SymbolTable,
+       sema.DType;
 
 enum ExpType
 {
@@ -29,6 +30,8 @@
         this.expType = expType;
     }
 
+    DType type() { return null; }
+
     ExpType expType;
     Scope env;
     int stmtIndex;
@@ -48,6 +51,13 @@
         this.args = args;
     }
 
+    override DType type()
+    {
+        DFunction f = cast(DFunction)exp.type();
+        assert(f, "Can only call functions");
+        return f.return_type;
+    }
+
     Exp exp;
     Exp[] args;
     bool sret = false;
@@ -105,6 +115,8 @@
         return this;
     }
 
+    override DType type() { return identifier.type(); }
+
     Exp identifier;
     Exp exp;
 }
@@ -132,6 +144,23 @@
         this.right = right;
     }
 
+    override DType type()
+    {
+        if (myType)
+            return myType;
+
+        DType l = left.type;
+        DType r = right.type;
+        if (l is r)
+            myType = l;
+        else if (l.hasImplicitConversionTo(r))
+            myType = r;
+        else if (r.hasImplicitConversionTo(l))
+            myType = l;
+        else
+            return null;
+    }
+
     char[] resultType()
     {
         if (op >= Operator.Eq && op <= Operator.Ge)
@@ -147,6 +176,7 @@
 
     Operator op;
     Exp left, right;
+    private DType myType;
 }
 
 class NegateExp : Exp
@@ -162,6 +192,8 @@
         return this;
     }
 
+    override DType type() { return exp.type(); }
+
     public Exp exp;
 }
 
@@ -177,6 +209,8 @@
         return this;
     }
 
+    override DType type() { return DType.Int; }
+
     Token token;
 }
 
@@ -195,8 +229,22 @@
         return this;
     }
 
+    override DType type()
+    {
+        if (myType)
+            return myType;
+
+        DStruct st = cast(DStruct)target.type;
+        assert(st, "Only structs have members");
+        if (auto t = st.typeOf(child.token.get))
+            myType = t;
+        // no error reporting here
+        else assert(0, "Referencing non-existant member");
+    }
+
     Identifier child;
     Exp target;
+    private DType myType;
 }
 
 class ArrayLookup : Exp
@@ -208,6 +256,8 @@
         this.pos = pos;
     }
 
+    override DType type() { return target.type(); }
+
     Exp simplify()
     {
         target = target.simplify;
@@ -228,6 +278,14 @@
         name = t.get;
     }
 
+    override DType type()
+    {
+        if (myType)
+            return myType;
+        myType = env.find(this).type;
+        return myType;
+    }
+
     this(char[] name)
     {
         super(ExpType.Identifier);
@@ -265,6 +323,6 @@
 
     Token token;
     char[] name;
+    private DType myType;
 }
 
-