[swift-evolution] Lambda function syntax

[Craig Cruden]

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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