/// <summary>
/// The node has to be transformed before being passed
/// </summary>
/// <param name="n"></param>
/// <returns></returns>
public Expression ToExpr(Node n)
{
switch (n.Label)
{
case "Empty":
return Noop;
case "Return":
return (n.Count > 0)
? Expression.Return(GetReturnTarget(), ToExpr(n[0]), typeof(Object))
: Expression.Return(GetReturnTarget(), Expression.Constant(typeof(Object), null));
case "If":
return n.Count > 2
? Expression.IfThenElse(Expression.Convert(ToExpr(n[0]), typeof(Boolean)), ToExpr(n[1]), ToExpr(n[2]))
: Expression.IfThen(Expression.Convert(ToExpr(n[0]), typeof(Boolean)), ToExpr(n[1]));
case "Else":
return ToExpr(n[0]);
case "For":
return CompileForLoop(ToExpr(n[0]), ToExpr(n[1]), ToExpr(n[2]), ToExpr(n[3]));
case "VarDecl":
{
var r = AddBinding(Expression.Variable(typeof(object), n[0].Text));
if (n.Count > 1)
r = Expression.Assign(r, ToExpr(n[1]));
return r;
}
case "Block":
return ScopedExpr(() => Expression.Block(n.Nodes.Select(ToExpr)));
case "TertiaryExpr":
return Expression.Condition(ToExpr(n[0]), ToExpr(n[1]), ToExpr(n[2]));
case "BinaryExpr":
return Expression.Call(null, Primitives.GetMethodFromBinaryOperator(n[1].Text), ToExpr(n[0]), ToExpr(n[2]));
case "AssignExpr":
return Expression.Assign(ToExpr(n[0]), ToExpr(n[2]));
case "FieldExpr":
return Expression.Field(ToExpr(n[0]), n[1].Text);
case "IndexExpr":
return CompileIndexExpr(ToExpr(n[0]), ToExpr(n[2]));
case "CallExpr":
return CompileCallExpr(ToExpr(n[0]), n[1].Nodes.Select(ToExpr));
case "MethodCallExpr":
{
var self = ToExpr(n[0]);
var func = Expression.Field(self, n[1].Text);
var args = new List<Expression>() { self };
args.AddRange(n[2].Nodes.Select(ToExpr));
return CompileCallExpr(func, args);
}
case "PrefixExpr":
switch (n[0].Text)
{
case "!": return Expression.Not(ToExpr(n[1]));
case "~": return Expression.OnesComplement(ToExpr(n[1]));
case "-": return Expression.Negate(ToExpr(n[1]));
default: throw new Exception("Unrecognized prefix operator " + n[0].Text);
}
case "NewExpr":
return ScopedExpr(() =>
{
AddBinding("this", Expression.Constant(new JsonObject()));
return ToExpr(n[0]);
});
case "ParenExpr":
return ToExpr(n[0]);
case "AnonFunc":
{
var ps = n[0].Nodes.Select(x => Expression.Parameter(typeof(Object), x.Text));
return CreateStatementLambda(ps, () => ToExpr(n[1]));
};
case "Object":
throw new NotImplementedException();
case "Array":
return Expression.NewArrayInit(typeof(object), n.Nodes.Select(ToExpr));
case "Identifier":
return Lookup(n.Text);
case "String":
return Expression.Constant(Utilities.Unquote(n.Text));
case "Integer":
return Expression.Convert(Expression.Constant(int.Parse(n.Text)), typeof(Object));
case "Float":
return Expression.Convert(Expression.Constant(float.Parse(n.Text)), typeof(Object));
case "True":
return Expression.Convert(Expression.Constant(true), typeof(Object));
case "False":
return Expression.Convert(Expression.Constant(false), typeof(Object));
case "Null":
return Expression.Constant(null);
default:
throw new Exception("Unrecognized node type " + n.Label);
}
}
