try & catch / repeating code - DRY

[Jacob Carlborg]

On 2018-05-24 08:05, Robert M. Münch wrote:

> Hi, great! Thanks for the examples... BTW: Is there a place where such 
> generic and fundamental examples are collected?

Not as far as I know.

>> void handleException1(alias dg)()
>> {
>>      try dg();
>>      catch (Exception e) { /* handle exception */ }
>> }
>>
>> void handleException2(lazy void dg)
>> {
>>      try dg();
>>      catch (Exception e) { /* handle exception */ }
>> }
>>
>> void handleException3(scope void delegate () dg)
>> {
>>      try dg();
>>      catch (Exception e) { /* handle exception */ }
>> }
>>
>> void main()
>> {
>>      handleException1!({
>>          writeln("asd");
>>      });
>>
>>      handleException1!(() => writeln("asd"));
>>
>>      handleException2(writeln("asd"));
>>
>>      handleException3({
>>          writeln("asd");
>>      });
>> }
> 
> What is exactly the difference between handleException1 and 3?

With handleException1 the delegate needs to be passed as a template 
argument, in the other case as a regular argument. I thought that the 
lambda syntax, () => writeln("asd"), did not work as a regular argument, 
but I checked now and it does.

Passing it as a template argument might allow the compiler to inline it. 
All range functions in Phobos are using template argument approach.

-- 
/Jacob Carlborg