[swift-evolution] Lambda function syntax

[Craig Cruden]

It would not prevent curly brackets for single-line cases…. just the difference between a map function call map() vs infix with scope.





> On 2015-12-23, at 9:48:24, Alexander Regueiro <alexreg at gmail.com> wrote:
> 
> 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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>> 
>