• JS (22/22) Jul 21 2013 Say I have a template function where there are variations, it
• JS (8/8) Jul 21 2013 BTW, I'm not saying D can't do anything like this
• bearophile (17/30) Jul 21 2013 You are discussing about two different problems: one is the

"JS" <js.mdnq gmail.com> writes:

Say I have a template function where there are variations, it 
would be nice to be able to specify those variables like

strip!Left(s), strip!Right(s), strip(s), etc...

instead of ahving to do stripLeft, stripRight, and strip.

But the goal isn't just to add an extra ! to type but that it 
reduces code duplication.

strip left and strip right are very similar and in a stripping 
algorithm most of the code is identical except for the direction 
the loop... instead of copying and pasting an appropriately 
placed static if could simplify things greatly.

e.g.,

string strip(string dir = {"Left", "Right", default: 
"Both"})(string s);


using such a notation could allow us to use such a notation could 
make life more interesting... (BTW, I'm not saying this notation 
has to be exactly like this...)

The idea is also to avoid littering the symbol table with symbols 
so "strings without quotes" are passed. e.g., split!Left instead 
of split!"Left" and Left doesn't have to be defined somewhere.

If this notation doesn't work well with template notation then 
some alternate could be used

strip Left or strip#Left..

"JS" <js.mdnq gmail.com> writes:

BTW, I'm not saying D can't do anything like this

enum Dir { Left, Right, Both }

string strip(Dir dir = Dir.Both)(string s)

but one has to call it like

strip!(Dir.Left)(s); (or if using strings, strip!"Left"(s))

Possibly, to make it easier the compiler and localize the enum if 
one is used:

strip!Left(s); // compiler changes to strip!(Dir.Left)(s)

"bearophile" <bearophileHUGS lycos.com> writes:

JS:

 Say I have a template function where there are variations, it 
 would be nice to be able to specify those variables like

 strip!Left(s), strip!Right(s), strip(s), etc...

 instead of ahving to do stripLeft, stripRight, and strip.

 But the goal isn't just to add an extra ! to type but that it 
 reduces code duplication.

 strip left and strip right are very similar and in a stripping 
 algorithm most of the code is identical except for the 
 direction the loop... instead of copying and pasting an 
 appropriately placed static if could simplify things greatly.

 e.g.,

 string strip(string dir = {"Left", "Right", default: 
 "Both"})(string s);

You are discussing about two different problems: one is the 
duplication of code in strip, and the other in having a syntax 
for "inlined" enums.

The first problem is easy to solve, just write one strip function 
with a template argument to tell apart its various versions, and 
then add:

alias stripLeft = strip!(Dir.Left);
alias stripRight = strip!(Dir.Right);
...

So each version only requires one more line of code, this is 
acceptable.

Regarding the inlined enum, a similar feature was requested 
several times, maybe in some form even in Bugzilla, but I don't 
remember Walter ever commenting on it.

Bye,
bearophile