Re: [RFC] Return Type Declarations

On Wed, May 7, 2014 at 11:02 AM, Lin Yo-An <cornelius.howl@gmail.com> wrote: > Hi, > > Why using an additional ":" symbol for the return type? what about > considering this: > > function foo() string { } > > and for closure: > > $bar = 1; > $foo = function() use ($bar) string { > > }; > > I think removing ":" symbol is cleaner. Your point is valid, certainly. We could omit it. Here are two minor things to think about: 1. Syntax is a visual indicator. 2. Compatibility and familiarity to similar languages. Syntax can be used to visually indicate things to the programmer. For instance, the () in a conditional statement is not strictly necessary from a language design perceptive and Go chose to omit them. Valid Go: if $var === $null { } In our case the colon indicates that you are declaring a return type and you can read it aloud as "returns". While not strictly necessary it does give a visual indicator of what is going on. function date_diff(DateTime $a, DateTime $b) : DateInterval; The above function can be read aloud as: "Function date_diff takes DateTime a and DateTime b and returns DateInterval" The colon indicates 'returns'. You can infer this from the context, sure; again I did say this was a minor thing. In the case of the colon I value being compatible with Hack more than the small gain of omitting the colon.