--- a/ast/Decl.d	Sun Aug 10 17:09:41 2008 +0200
+++ b/ast/Decl.d	Mon Aug 11 18:41:45 2008 +0200
@@ -1,4 +1,7 @@
 module ast.Decl;
+
+import ast.Expr;
+
 /**
   The base class for all Declarations. 
   
@@ -8,7 +11,127 @@
     $(LI members, such as variables and functions.)
     $(LI types, such as classes, structs.))
 
- **/
+  */
 class Decl
 {
+
+    /// Method for doing cast(FunctionDecl)
+    FunctionDecl asFunctionDecl() { return null;}
+
+    /// Returns true if it is a FunctionDecl
+    bool isFunctionDecl() { return false;}
+
+    /// Method for doing cast(VarDecl)
+    VarDecl asVarDecl() { return null;}
+
+    /// Returns true if it is a VarDecl
+    bool isVarDecl() { return false;}
+
+    /// Method for doing cast(StructDecl)
+    StructDecl asStructDecl() { return null;}
+
+    /// Returns true if it is a StructDecl
+    bool isStructDecl() { return false;}
+
+    /// Method for doing cast(ClassDecl)
+    ClassDecl asClassDecl() { return null;}
+
+    /// Returns true if it is a ClassDecl
+    bool isClassDecl() { return false;}
+
+    /// Method for doing cast(InterfaceDecl)
+    InterfaceDecl asInterfaceDecl() { return null;}
+
+    /// Returns true if it is a InterfaceDecl
+    bool isInterfaceDecl() { return false;}
+
+    /// Method for doing cast(TypedefDecl)
+    TypedefDecl asTypedefDecl() { return null;}
+
+    /// Returns true if it is a TypedefDecl
+    bool isTypedefDecl() { return false;}
 }
+
+/**
+  The FunctionDecl contains a set of VarDecls, being the parameters of the
+  method. It also contains a potentiel list of statements.
+  */
+class FunctionDecl : Decl
+{
+    /// Returns the parameters of the method.
+    VarDecl[] getParams() { return params;}
+    /// Return the parameter on a given index.
+    VarDecl getParam(int index) { return params[index];}
+    /// Returns the number of parameters.
+    int getNumberOfParamst() { return params.length;}
+    /**
+      Returns the number of required arguments, that should be given to
+      call this method.
+      */
+    int getMinimumNumberOfParams() 
+    { 
+        assert(0, "Unimplemented");
+        return 0;
+    }
+
+    override FunctionDecl asFunctionDecl() { return this;}
+    override bool isFunctionDecl() { return true;}
+
+private:
+    VarDecl[] params;
+}
+
+/**
+  The VarDecl contains as a minimum a Type. As an addition, i will also
+  in most cases contain an Identifier that it'll be reconized by and in
+  some cases it will also contain an expression that'll be it initializer.
+
+  Some cases to check:
+
+  $(UL
+      $(LI
+          If the VarDecl is a param in a FunctionDecl the initializer, if
+          present, should be a constant expression(Enum, Number, String 
+          or the like).
+        )
+    )
+  */
+class VarDecl : Decl
+{
+    /// Return true if the VarDecl has an identifier/name.
+    bool hasIdentifier() { return !(identifier is null);}
+    /// Return true if the VarDecl has en initializer.
+    bool hasInitializer() { return !(initializer is null);}
+
+    override VarDecl asVarDecl() { return this;}
+    override bool isVarDecl() { return true;}
+    
+private:
+    Identifier identifier;
+    Expr initializer;
+}
+
+class StructDecl : Decl
+{
+    override StructDecl asStructDecl() { return this;}
+    override bool isStructDecl() { return true;}
+}
+
+class ClassDecl : Decl
+{
+    override ClassDecl asClassDecl() { return this;}
+    override bool isClassDecl() { return true;}
+}
+
+class InterfaceDecl : Decl
+{
+    override InterfaceDecl asInterfaceDecl() { return this;}
+    override bool isInterfaceDecl() { return true;}
+}
+
+class TypedefDecl : Decl
+{
+    override TypedefDecl asTypedefDecl() { return this;}
+    override bool isTypedefDecl() { return true;}
+}
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ast/Expr.d	Mon Aug 11 18:41:45 2008 +0200
@@ -0,0 +1,72 @@
+module ast.Expr;
+
+/**
+  The base class for all Expressions.
+  */
+class Expr
+{
+    /// Returns true if the Expr can be compile-time evaluated.
+    bool isConstantExpr() { return false; }
+
+    NumberLiteral asNumberLiteral() { return null; }
+    bool isNumberLiteral() { return false; }
+
+    StringLiteral asStringLiteral() { return null; }
+    bool isStringLiteral() { return false; }
+
+    ArrayLiteral asArrayLiteral() { return null; }
+    bool isArrayLiteral() { return false; }
+}
+
+/**
+  NumberLiteral
+  */
+class NumberLiteral : Expr
+{
+    override bool isConstantExpr() { return true; }
+
+    override NumberLiteral asNumberLiteral() { return this; }
+    override bool isNumberLiteral() { return true; }
+}
+
+/**
+  StringLiteral
+  */
+class StringLiteral : Expr
+{
+    override bool isConstantExpr() { return true; }
+
+    override StringLiteral asStringLiteral() { return this; }
+    override bool isStringLiteral() { return true; }
+}
+
+
+/**
+  StringLiteral
+  */
+class ArrayLiteral : Expr
+{
+    override bool isConstantExpr() 
+    {
+        foreach (arg; arguments)
+            if (!arg.isConstantExpr())
+                return false;
+        return true; 
+    }
+
+    override ArrayLiteral asArrayLiteral() { return this; }
+    override bool isArrayLiteral() { return true; }
+
+private:
+    Expr[] arguments;
+}
+
+
+
+/**
+  Identifier
+  */
+class Identifier : Expr
+{
+
+}

--- a/doc/candydoc/modules.ddoc	Sun Aug 10 17:09:41 2008 +0200
+++ b/doc/candydoc/modules.ddoc	Mon Aug 11 18:41:45 2008 +0200
@@ -1,2 +1,3 @@
 MODULES =
 	$(MODULE_FULL ast.Decl)
+	$(MODULE_FULL ast.Expr)