digitalmars.D.learn - reduce condition nesting

Andrey (2/19) Nov 22 2017

Nicholas Wilson (8/27) Nov 22 2017 do
Andrea Fontana (6/25) Nov 23 2017 if (c1) foo()

Andrey (4/30) Nov 23 2017 haha, yes you are right, sorry for stupid question, I recently

Adam D. Ruppe (2/9) Nov 23 2017 The `switch` statement covers some of these cases too.

Andrea Fontana (4/13) Nov 23 2017 Anyway you can create something like this:

drug (2/17) Nov 23 2017 I really like Dlang very much
Temtaime (11/25) Nov 23 2017 Syntax #4
Michael (3/17) Nov 23 2017 That's pretty cool!
=?UTF-8?Q?Ali_=c3=87ehreli?= (10/25) Nov 25 2017 I tried to implement the following but gave up because I could not

Adam D. Ruppe (40/48) Nov 25 2017 Bones: "Perhaps the professor can use your computer."

=?UTF-8?Q?Ali_=c3=87ehreli?= (7/35) Nov 25 2017 Cool! So, D is great even without templates. ;)

Adam D. Ruppe (4/7) Nov 25 2017 Yeah, I'm tempted to say that is a bug... I doubt anyone has

Andrey <andrey kabylin.ru> writes:

Hello, is there way to reduce this condition:
 if (c1) {
     foo();
 } else {
     if (c2) {
         bar();
     } else {
         if (c3) {
         ...
         }
     }
 }

for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }

Nov 22 2017

Nicholas Wilson <iamthewilsonator hotmail.com> writes:

On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
 Hello, is there way to reduce this condition:
 if (c1) {
     foo();
 } else {
     if (c2) {
         bar();
     } else {
         if (c3) {
         ...
         }
     }
 }

 for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }


do
{
     if (c1) { foo(); break;}
     if (c2) { bar(); break;}
     if (c3) { baz(); break;}
     someDefault();
} while (false);

Nov 22 2017

Andrea Fontana <nospam example.com> writes:

On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
 Hello, is there way to reduce this condition:
 if (c1) {
     foo();
 } else {
     if (c2) {
         bar();
     } else {
         if (c3) {
         ...
         }
     }
 }

 for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }


if (c1) foo()
else if (c2) bar();
else if (c3) ...
else someDefault();

?

Nov 23 2017

Andrey <andrey kabylin.ru> writes:

On Thursday, 23 November 2017 at 08:27:54 UTC, Andrea Fontana 
wrote:
 On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
 Hello, is there way to reduce this condition:
 if (c1) {
     foo();
 } else {
     if (c2) {
         bar();
     } else {
         if (c3) {
         ...
         }
     }
 }

 for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }


 if (c1) foo()
 else if (c2) bar();
 else if (c3) ...
 else someDefault();

 ?

haha, yes you are right, sorry for stupid question, I recently 
began to study Kotlin and noticed than `when` is a great feature )

Nov 23 2017

Adam D. Ruppe <destructionator gmail.com> writes:

On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
 for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }


The `switch` statement covers some of these cases too.

Nov 23 2017

Andrea Fontana <nospam example.com> writes:

On Thursday, 23 November 2017 at 13:47:37 UTC, Adam D. Ruppe 
wrote:
 On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
 for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }


 The `switch` statement covers some of these cases too.

Anyway you can create something like this:
https://run.dlang.io/is/7pbVXT

Nov 23 2017

drug <drug2004 bk.ru> writes:

23.11.2017 17:16, Andrea Fontana пишет:
 On Thursday, 23 November 2017 at 13:47:37 UTC, Adam D. Ruppe wrote:
 On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
 for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }


 The `switch` statement covers some of these cases too.

 
 Anyway you can create something like this:
 https://run.dlang.io/is/7pbVXT
 

I really like Dlang very much

Nov 23 2017

Temtaime <temtaime gmail.com> writes:

On Thursday, 23 November 2017 at 14:16:25 UTC, Andrea Fontana 
wrote:
 On Thursday, 23 November 2017 at 13:47:37 UTC, Adam D. Ruppe 
 wrote:
 On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
 for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }


 The `switch` statement covers some of these cases too.

 Anyway you can create something like this:
 https://run.dlang.io/is/7pbVXT




     when
	(
         c1, { writeln("first"); 	},
         c2, { writeln("second"); },
         { writeln("default"); }	
     );

:)

Nov 23 2017

Michael <michael toohuman.io> writes:

On Thursday, 23 November 2017 at 14:16:25 UTC, Andrea Fontana 
wrote:
 On Thursday, 23 November 2017 at 13:47:37 UTC, Adam D. Ruppe 
 wrote:
 On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
 for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }


 The `switch` statement covers some of these cases too.

 Anyway you can create something like this:
 https://run.dlang.io/is/7pbVXT

That's pretty cool!

Nov 23 2017

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 11/23/2017 06:16 AM, Andrea Fontana wrote:
 On Thursday, 23 November 2017 at 13:47:37 UTC, Adam D. Ruppe wrote:
 On Thursday, 23 November 2017 at 05:19:27 UTC, Andrey wrote:
 for instance in kotlin it can be replace with this:
 when {
     c1 -> foo(),
     c2 -> bar(),
     c3 -> ...
     else -> someDefault()
 }


 The `switch` statement covers some of these cases too.

 
 Anyway you can create something like this:
 https://run.dlang.io/is/7pbVXT
 

I tried to implement the following but gave up because I could not 
ensure short circuit behaviour.

     when(
         c1.then(foo()),
         c2.then(bar()),
         otherwise(zar())
     );

Possible?

Ali

Nov 25 2017

Adam D. Ruppe <destructionator gmail.com> writes:

On Saturday, 25 November 2017 at 21:42:29 UTC, Ali Çehreli wrote:
 I tried to implement the following but gave up because I could 
 not ensure short circuit behaviour.

     when(
         c1.then(foo()),
         c2.then(bar()),
         otherwise(zar())
     );

 Possible?

Bones: "Perhaps the professor can use your computer."

https://dlang.org/spec/function.html#lazy_variadic_functions

Dr. Nichols: "Lazy variadic functions?!"
Scotty: "That's the ticket, laddie."

---
import std.stdio;

void when(bool delegate()[] foo...) {
	foreach(i; foo) {
		if(i())
			return;
	}
}

bool then(bool c, lazy void what) {
	if(c) what();
	return c;
}

bool otherwise(lazy void what) {
	what;
	return true;
}


void foo() {
	writeln("foo evaled");
}
void bar() {
	writeln("bar evaled");
}
void zar() {
	writeln("zar evaled");
}

void main() {
	bool c1 = false;
	bool c2 = false;

     when(
         c1.then(foo()),
         c2.then(bar()),
         otherwise(zar())
     );
}
---

Nov 25 2017

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 11/25/2017 02:05 PM, Adam D. Ruppe wrote:
 On Saturday, 25 November 2017 at 21:42:29 UTC, Ali Çehreli wrote:
 I tried to implement the following but gave up because I could not 
 ensure short circuit behaviour.

     when(
         c1.then(foo()),
         c2.then(bar()),
         otherwise(zar())
     );

 Possible?

 
 Bones: "Perhaps the professor can use your computer."
 
 https://dlang.org/spec/function.html#lazy_variadic_functions
 
 Dr. Nichols: "Lazy variadic functions?!"
 Scotty: "That's the ticket, laddie."
 
 ---
 import std.stdio;
 
 void when(bool delegate()[] foo...) {
      foreach(i; foo) {
          if(i())
              return;
      }
 }

Cool! So, D is great even without templates. ;)

Despite 'lazy', apparently my failed attempt had eager arguments:

void when(lazy bool[] args...) {
     // ...
}

Ali

Nov 25 2017

Adam D. Ruppe <destructionator gmail.com> writes:

On Saturday, 25 November 2017 at 22:45:03 UTC, Ali Çehreli wrote:
 Despite 'lazy', apparently my failed attempt had eager 
 arguments:

 void when(lazy bool[] args...) {

Yeah, I'm tempted to say that is a bug... I doubt anyone has 
combined lazy with T[]... like this before - especially since the 
language has that other syntax to cover this case.

Nov 25 2017

D Programming

C/C++ Programming

Other

digitalmars.D.learn - reduce condition nesting