Index-less versions of map, filter, each etc. by default; declare eachWithIndex

[fatuhoku]

Very very often, it is unnecessary to take into account the index of the element when mapping. For instance:

    [[foos filter:^BOOL(NSString *foo) {
        return [foo length] > 0;
    }] each:^(NSString *bar) {
        // do something with bar
    }];

This code works perfectly with well with Functional.m. However, under Overline, we must also define a NSUInteger parameter, which makes the statement less readable.

    [[foos filter:^BOOL(NSString *foo, NSUInteger __unused) {
        return [foo length] > 0;
    }] each:^(NSString *bar, NSUInteger __unused) {
        // do something with bar
    }];

I think Overline should consider following the same interface as Functional.m.

@interface NSArray(F)
    ...
    - (void) each:(VoidIteratorArrayBlock) block;
    - (void) eachWithIndex:(VoidIteratorArrayWithIndexBlock) block;   // ***
    - (NSArray *) map:(MapArrayBlock) block;
    ...
@end

In fact, the act of 'mapping' data from one array into another should never depend on its position and thus there should not be a mapWithIndex: method at all.

[fatuhoku]

I guess in this case I could use Overline-BlocksKit in combination with Functional.m to avoid using the Overline implementations.