objective c - Why does this method pass 'stop' by reference instead of return? -

does have insight why block parameter of

- (void)enumeratematchesinstring:(nsstring *)string                          options:(nsmatchingoptions)options                            range:(nsrange)range                       usingblock:(void (^)(nstextcheckingresult *result, nsmatchingflags flags, bool *stop))block 

passes stop reference instead of returning it?

it seems 'obvious' me use return value proabbly means missing , know missing. (the thing can think of able provide name pass reference variables make meaning clearer.)

my guess because stop functionality not needed, , making block return void keeps syntax lighter, because can fall off end of code return:

usingblock:^(nstextcheckingresult *result, nsmatchingflags flags, bool *stop) {     nslog(@"result: %@", result); }]; 

rather than:

usingblock:^(nstextcheckingresult *result, nsmatchingflags flags) {     nslog(@"result: %@", result);     return yes; }]; 

also, point out, there matter of clarity. without checking docs, hard tell return value means enumeration here. (also, speaking of block return values: where's -[nsarray collectresultsusingblock:] method?)

an added minor factor might bool types did not play block type inference while, this:

usingblock:^(nstextcheckingresult *result, nsmatchingflags flags) {     return yes; }]; 

would throw type error requiring either:

return (bool)yes; 

or:

usingblock:^bool (nstextcheckingresult… 

in order make work out right.

all of rank speculation. documentation appears silent on matter; coding guidelines cocoa not appear have been updated include standardization efforts apple appears have adopted internally, such providing names block arguments in prototype declarations.