## digitalmars.D.internals - [OT] What do you think about declaring functions with lambda syntax?

- ddcovery (19/19) Dec 04 2020 Example:
- ddcovery (20/22) Dec 04 2020 This is more functional :-)
- IGotD- (3/22) Dec 04 2020 It is really ugly and doesn't help readability. It looks like
- ddcovery (37/39) Dec 04 2020 For me it is absolutely wonderful and totally readable
- user1234 (5/6) Dec 04 2020 There's a related proposal [1] and the NG discussion is there [2].
- ddcovery (3/8) Dec 04 2020 I love it!!!

Example: import std.stdio, std.algorithm, std.array, std.conv ; ulong factorial(ulong n) => n>1 ? factorial(n-1)*n : 1 ; T[] sorted(T)(T[] xs) => xs.length == 0 ? [] : xs[1..$].filter!(x=> x < xs[0]).array.sorted ~ xs[0..1] ~ xs[1..$].filter!(x=> x >= xs[0]).array.sorted ; void main() => [5,6,7,2,3].sorted.map!(i=>i.to!ulong.factorial).writeln ;

Dec 04 2020

On Friday, 4 December 2020 at 11:12:23 UTC, ddcovery wrote:Example: ...This is more functional :-) import std.stdio, std.algorithm, std.array, std.conv ; pure ulong factorial(ulong n) => n>1 ? n * factorial(n-1) : 1 ; pure T[] sorted(T)(T[] xs) => xs.length == 0 ? [] : xs[1..$].filter!(x=> x < xs[0]).array.sorted ~ xs[0..1] ~ xs[1..$].filter!(x=> x >= xs[0]).array.sorted ; void main() => [5,6,7,2,3].sorted.map!(i=>i.to!ulong.factorial).writeln ;

Dec 04 2020

On Friday, 4 December 2020 at 11:12:23 UTC, ddcovery wrote:Example: import std.stdio, std.algorithm, std.array, std.conv ; ulong factorial(ulong n) => n>1 ? factorial(n-1)*n : 1 ; T[] sorted(T)(T[] xs) => xs.length == 0 ? [] : xs[1..$].filter!(x=> x < xs[0]).array.sorted ~ xs[0..1] ~ xs[1..$].filter!(x=> x >= xs[0]).array.sorted ; void main() => [5,6,7,2,3].sorted.map!(i=>i.to!ulong.factorial).writeln ;It is really ugly and doesn't help readability. It looks like another language.

Dec 04 2020

On Saturday, 5 December 2020 at 00:55:23 UTC, IGotD- wrote:It is really ugly and doesn't help readability. It looks like another language.For me it is absolutely wonderful and totally readable (expressive)... this is the way I like to write code when possible and this is, basically, D. Yesterday, I found myself writing this: ulong factorial(ulong n){return n>1 ? n*factorial(n-1) : 1 ;} Lambda notation is "syntax sugar" that compiler can transform to "{return ... }" transparently You choose your favorite one for each situation (like f(x) or x.f() or x.f, or like named parameters that will be introduced in future versions of D) Dart already offers this capability. // named function c like notation int factorial(int n) { return ...; } // named function lambda notation int factorial(int n) => ...; // Anonymous function c like notation final int Function(int) f = (n){ return n*n; } // Anonymous function lambda notation final int Function(int n) f = (n) => n*n; Scala does something similar (not really lambda notation, only the possibility to remove brackets because "return" is implicit) def factorial(n:Int):Int = if (n>1) n * factorial(n-1) else 1; def factorial(n:Int):Int = { if (n>1) n * factorial(n-1) else 1; } In typescript and python you can assign a lambda to a variable and refer it from the body // Typescript const factorial = (n:bigint)=> n>1? n*factorial(n-1):1; // Python factorial = lambda n : factorial(n-1)*n if n>1 else 1; This is not the est solution, but this is something (simple and effective) As DConf2020 exposed "D, the functional programming language nobody is talking about". In my opinion, the possibility of functions without brackets/return would be a good reinforcement.

Dec 04 2020

On Friday, 4 December 2020 at 11:12:23 UTC, ddcovery wrote:Example:There's a related proposal [1] and the NG discussion is there [2]. [1] https://github.com/dlang/dmd/pull/11833 [2] https://forum.dlang.org/post/cmgqwabzdqbtngmjidfw forum.dlang.org

Dec 04 2020

On Saturday, 5 December 2020 at 03:06:02 UTC, user1234 wrote:On Friday, 4 December 2020 at 11:12:23 UTC, ddcovery wrote:I love it!!! ThanksExample:There's a related proposal [1] and the NG discussion is there [2]. [1] https://github.com/dlang/dmd/pull/11833

Dec 04 2020