[swift-evolution] Lambda function syntax

[Alexander Regueiro]

Why not curly braces for single-line and multi-line cases? About the brackets around multiple parameters: like I said before, no strong opinion either way.

> On 23 Dec 2015, at 02:46, Craig Cruden <ccruden at novafore.com> wrote:
> 
> I am joining this discussion a little late - so I would not be surprised if discussed earlier.
> 
> but:  
> 
> My preference would be:
> 
> foo.map( bar => bar.boz) // single line
> 
> or 
> 
> foo.map { bar =>
>                 ….
>              } 
> 
> if more than one line
> 
> if there are multiple values then:
> 
> foo.map { (x, y) => x * 5 + y }
> 
> 
> 
> 
>> On 2015-12-23, at 9:39:03, Andrey Tarantsov via swift-evolution <swift-evolution at swift.org> wrote:
>> 
>> One thing I'm really bothered by in C# and ES6 are no-argument methods:
>> 
>> () => { foo() }   // GROSS
>> 
>> The syntax of C# isn't so bad, though, when there's no return type:
>> 
>> foo.map((bar) => bar.boz)
>> 
>> but those double-parens bother me and my eyes a bit, so this definitely looks better:
>> 
>> foo.map { (bar) => bar.boz }
>> 
>> I think I'd even prefer that to:
>> 
>> foo.map { (bar) in bar.boz }
>> 
>> 
>> What if we just agreed to replace "in" with "=>"? Would that be an improvement in your eyes? I could stand behind that proposal.
>> 
>> (btw Chris & team — THANK YOU for the Ruby-style trailing closure syntax, it was such a treat to see it last summer!)
>> 
>> A.
>> 
>> 
>>> On Dec 23, 2015, at 8:33 AM, Alexander Regueiro <alexreg at gmail.com> wrote:
>>> 
>>> This was my first proposal, and was changed my second, but this syntax is inspired by C#, where a lambda expression is of one of the following forms:
>>> 
>>> (Type1 param1, …) => foo // single-statement expression
>>> (Type1 param1, …) => { …; return foo; } // multi-statement expression
>>> 
>>> Haskell also uses syntax closer to this than to Swift, not to mention ML/F#.
>>> 
>>>> On 23 Dec 2015, at 02:30, Andrey Tarantsov <andrey at tarantsov.com> wrote:
>>>> 
>>>> So I believe the opinion of the core team and the community would be generally in opposition to the style you want. I understand your arguments, but somehow they are against the entire experience of me (and, presumably, others) as developers.
>>>> 
>>>> To continue our friendly banter, though, do you mind sharing your background? When I read this, I wasn't sure if you're serious or trolling:
>>>> 
>>>>> I would propose changing it from:
>>>>> 
>>>>> { (param_list) -> return_type in … }
>>>>> 
>>>>> to something cleaner like:
>>>>> 
>>>>> (param_list) -> return_type => { … }
>>>> 
>>>> I wonder if doing something like Haskel a lot makes you more used to that sort of arrow constructs?
>>>> 
>>>> This is written in good faith; I hope I used the right tone to indicate that.
>>>> 
>>>> A.
>>>> 
>>> 
>> 
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