Block arguments should always be named.

[jackhl]

Block declaration arguments should always include variable names to follow the Objective-C style of named arguments.

Also what's your stance on typedef'ing blocks? I'm somewhat against it just because you can't easily determine the block arguments by command-clicking on a method or quickly looking at a header file.

[jspahrsummers]

When would a block ever have an unnamed argument? Is this something you've actually seen before?

[jackhl]

I'm talking about the possibility of a method signature that looks like this:

- (void)methodThatTakesBlock:(void (^)(NSString *, NSData *, NSError *))block;

It's very frustrating when someone does that for two reasons:

1. I have no idea what those arguments hold.
2. When I'm typing the method name xcode autocompletes it and then immediately yells at me about unnamed block arguments.

[jackhl]

This actually brings up the point that I don't think you should ever omit an argument's name in a C function. For example, I much prefer

void GHAwesomeFunction(int descriptiveName1, int descriptiveName2, float descriptiveName3);

vs

void GHAwesomeFunction(int, int, float);

If you agree, can I add that rule too?

[jspahrsummers]

Ah, gotcha. How about phrasing it like this, then:

Parameters in block types should be named unless the block is initialized immediately.

This allows uses like:

void (^block)(NSString *) = ^(NSString *name) {
};

… where the purpose of the parameter is obvious from the literal, and doesn't need to be duplicated in the type.

This actually brings up the point that I don't think you should ever omit an argument's name in a C function.

We try to limit our conventions to things that might be contentious or not obvious – i.e., our conventions always start with an implicit "Use common sense." I don't think I've ever seen C declarations without parameter names in reputable code. It shouldn't be necessary to say that it's a bad idea.

[jackhl]

🎯 Sounds good. I'll reword it but I think I'm going to use Arguments rather than Parameters since that's what's used in the bullet above and elsewhere (unless you have a different preference).

[jspahrsummers]

The use of the word "parameters" is intentional. Parameters are used in declarators, arguments are used in invocations.

Declarations are also different from definitions.

[jackhl]

Thanks for the clarification. For declarations vs definitions, I would say "declared property" because I'm telling the consumer/compiler that the property exists but I would say "class definition" because I'm describing the class. Am I on the right track?

[jspahrsummers]

Roughly, a declaration is an interface while a definition is the implementation.

This declares a constant which will be defined in another module:

extern NSString * const NotificationName;

This defines and initializes the constant:

NSString * const NotificationName = @"NotificationName";

Note that these concepts aren't always mutually exclusive. This both declares and defines a variable i (since the definition marks its first appearance, it also functions as a declaration):

- (void)method {
    int i;
}

[dannygreg]

Big 👍 from me to this.

[alanjrogers]

Yeah, definite 👍 from me.

[jspahrsummers]

💎