/// <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);
}
}
static object AddTest(object a, object b)
{
return(Primitives.add(a, b));
}