CODEWITHSUNDEEP
c#syntax
Wickoo
Wickoo

Reputation: 7397

Can this be interpreted as an invocation expression in C#?

According to the C# grammar, one can write

(A)(B)

which can be interpreted either as an invocation expression or a type cast. Can someone please provide a valid C# example that interprets this case as an invocation expression?

This is the grammar rule I'm referring to:

invocation-expression:
    primary-expression   (   argument-list?   )

and primariy-expression can be a parenthesised expression.

Upvotes: 2

Views: 95

Answers (2)

The Vermilion Wizard
The Vermilion Wizard

Reputation: 5415

It seems Visual Studio complains about this: (TestMethod)();

But this is evaluated as a function call (assuming TestMethod is a method): (this.TestMethod)();

Unless TestMethod is static, in which case even (MyClass.TestMethod)(); doesn't work.

I think it's because something like this.TestMethod unambiguously evaluates to a method group. There is no scenario where this.anything would evaluate to a type. But classname.something could be a nested type, or it could be a static method, so VS seems to interpret that as a type.

Upvotes: 1

IS4
IS4

Reputation: 13217

Like this?

((Action<string>)Console.WriteLine)("test");

Or this, as an expression:

((Func<int>)Console.Read)()

Edit: I doubt there is a way for primary-expression to be a simple identifier, as this always gets parsed as a cast (even (writeLine)()), but it's not a big deal, as you can always just remove the parentheses.

Upvotes: 4

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