Why can't c# use inline anonymous lambdas or delegates?
- by Samuel Meacham
I hope I worded the title of my question appropriately.
In c# I can use lambdas (as delegates), or the older delegate syntax to do this:
Func<string> fnHello = () => "hello";
Console.WriteLine(fnHello());
Func<string> fnHello2 = delegate()
{
return "hello 2";
};
Console.WriteLine(fnHello2());
So why can't I "inline" the lambda or the delegate body, and avoid capturing it in a named variable (making it anonymous)?
// Inline anonymous lambda not allowed
Console.WriteLine(
(() => "hello inline lambda")()
);
// Inline anonymous delegate not allowed
Console.WriteLine(
(delegate() { return "hello inline delegate"; })()
);
An example that works in javascript (just for comparison) is:
alert(
(function(){ return "hello inline anonymous function from javascript"; })()
);
Which produces the expected alert box.
UPDATE:
It seems you can have an inline anonymous lambda in C#, if you cast appropriately, but the amount of ()'s starts to make it unruly.
// Inline anonymous lambda with appropriate cast IS allowed
Console.WriteLine(
((Func<string>)(() => "hello inline anonymous lambda"))()
);
Perhaps the compiler can't infer the sig of the anonymous delegate to know which Console.WriteLine() you're trying to call? Does anyone know why this specific cast is required?
