private static Expression CompileExistence(Op op, Scope scope)
{
var p = scope.FreeVariable("ref");
var @ref = new Literal {Value = p.Name};
var fst = new Parens {Body = new Assign {Variable = @ref, Value = op.First}};
return Compile(new If {Condition = new Existence {Expression = fst}, Body = @ref, ElseBody = op.Second}, scope);
}
public static Expression CompileOp(Op op, Scope scope)
{
var ischain = op.IsChainable && op.First is Op && ((Op)op.First).IsChainable;
if (op.Second == null)
return CompileUnary(op, scope);
if (ischain)
return CompileChain(op, scope);
if (op.Operator == "?")
return CompileExistence(op, scope);
var first = Compile(op.First, scope);
var second = Compile(op.Second, scope);
var operation = GetExpressionType(op.Operator);
return Expression.Dynamic(
scope.GetRuntime().BinaryOperationBinders.Get(operation),
typeof(object),
first,
second
);
}
public static Expression CompileUnary(Op op, Scope scope)
{
throw new NotImplementedException();
}
public static Expression CompileChain(Op op, Scope scope)
{
//for a chain we need to convert the second param of the first to a local. then we can do two comparisons and merge them with &&
var first = op.First as Op;
var refName = scope.FreeVariableName("ref");
first.Second = first.Second.Cache(refName);
var fst = Compile(first, scope);
var scd = Compile(new Op {First = first.Second, Second = op.Second, Operator = op.Operator}, scope);
return Expression.Dynamic(
scope.GetRuntime().BinaryOperationBinders.Get(ExpressionType.And),
typeof (object),
fst, scd);
}
