Thread overview
control flow with a functional template ?
May 18, 2015
Baz
May 18, 2015
John Colvin
May 18, 2015
John Colvin
May 18, 2015
who's never had to do this:

---
if (comparison)
{
     statement;
     break;
}
---

ans then thought it's a pity to open/closes the braces just for a
simple statement. Would it be possible to have a template to
simplify this to:

---
if (comparison)
     Break!(expression);
---

or even at the language level:

---
if (comparison)
     break(expression);
if (comparison)
     continue(expression);
---

so far it looks like it's only possible using a string mixin,
which is a quite unelegant solution (because for example you loose the IDE completion while writting the statement):

---
auto Break(string statement)
{
    return format("{%s;break;}", statement);
}
// unelegant but works...
if (condition)
     mixin("myVar = 8".Break);

if (condition)
     mixin(q{myVar = 8}.Break);
---

Any other solution ?
May 18, 2015
On Monday, 18 May 2015 at 06:13:50 UTC, Baz wrote:
> who's never had to do this:
>
> ---
> if (comparison)
> {
>      statement;
>      break;
> }
> ---
>
> ans then thought it's a pity to open/closes the braces just for a
> simple statement. Would it be possible to have a template to
> simplify this to:
>
> ---
> if (comparison)
>      Break!(expression);
> ---
>
> or even at the language level:
>
> ---
> if (comparison)
>      break(expression);
> if (comparison)
>      continue(expression);
> ---
>
> so far it looks like it's only possible using a string mixin,
> which is a quite unelegant solution (because for example you loose the IDE completion while writting the statement):
>
> ---
> auto Break(string statement)
> {
>     return format("{%s;break;}", statement);
> }
> // unelegant but works...
> if (condition)
>      mixin("myVar = 8".Break);
>
> if (condition)
>      mixin(q{myVar = 8}.Break);
> ---
>
> Any other solution ?

Take a look at lazy function arguments if you really want this. Personally I think you'll end up saving a small handful of keystrokes (if any) at the expense of clarity.
May 18, 2015
On Monday, 18 May 2015 at 08:46:36 UTC, John Colvin wrote:
> On Monday, 18 May 2015 at 06:13:50 UTC, Baz wrote:
>> who's never had to do this:
>>
>> ---
>> if (comparison)
>> {
>>     statement;
>>     break;
>> }
>> ---
>>
>> ans then thought it's a pity to open/closes the braces just for a
>> simple statement. Would it be possible to have a template to
>> simplify this to:
>>
>> ---
>> if (comparison)
>>     Break!(expression);
>> ---
>>
>> or even at the language level:
>>
>> ---
>> if (comparison)
>>     break(expression);
>> if (comparison)
>>     continue(expression);
>> ---
>>
>> so far it looks like it's only possible using a string mixin,
>> which is a quite unelegant solution (because for example you loose the IDE completion while writting the statement):
>>
>> ---
>> auto Break(string statement)
>> {
>>    return format("{%s;break;}", statement);
>> }
>> // unelegant but works...
>> if (condition)
>>     mixin("myVar = 8".Break);
>>
>> if (condition)
>>     mixin(q{myVar = 8}.Break);
>> ---
>>
>> Any other solution ?
>
> Take a look at lazy function arguments if you really want this. Personally I think you'll end up saving a small handful of keystrokes (if any) at the expense of clarity.

Wait no, actually you do need mixins, I wasn't thinking. Unless you make the if statement a function call / template...