Re: Chainable template mixin and opCat()

[via Digitalmars-d]

On Monday, 1 June 2015 at 11:47:43 UTC, w0rp wrote:
I think my only complaint for this is that it wouldn't work for 
all ranges, so you'd be able to use the operator some times,


I still think the simplicity of

mixin Chainable;

and it's effect on usability is short enough to be worth the 
effort :)

Re: Chainable template mixin and opCat()

[via Digitalmars-d]

On Monday, 1 June 2015 at 11:20:52 UTC, Per Nordlöw wrote:

template Chainable() {
   Chain!(typeof(this), Range) opCat(Range)(Range r) {
   return chain(this, r);
   }
}


Would it suffice to restrict `opCat` as

Chain!(typeof(this), Range) opCat(Range)(Range r)
if (isInputRange!Range  is(CommonElementType!(typeof(this), 
Range)))


?

given that

template CommonElementType(Rs...)
{
alias CommonElementType = CommonType!(staticMap!(ElementType, 
Rs));

}

In general, should we let `Chain` do the error checking or should 
we copy its retrictions into `opCat`s restrictions?

Re: Chainable template mixin and opCat()

[w0rp via Digitalmars-d]

I think my only complaint for this is that it wouldn't work for 
all ranges, so you'd be able to use the operator some times, but 
not others. This is because you have to define the operators 
inside of the structs or classes, and you can't write operators 
as free functions. (Which is a good feature in general.)

Chainable template mixin and opCat()

[via Digitalmars-d]

I just stumbled upon the following very interested idea:

http://forum.dlang.org/thread/bug-604...@http.d.puremagic.com%2Fissues%2F

1. Add the following (where?)

template Chainable() {
   Chain!(typeof(this), Range) opCat(Range)(Range r) {
   return chain(this, r);
   }
}

2. Then in the body of a lazy range both Phobos ones like map, 
filter, zip, iota, and so on, and user-defined ones, you may add:


mixin Chainable;

This allows to write more natural and readable code like:

iota(5) ~ filter!q{a}([1,0,3])
map!abs([1,2,-5]) ~ [10, 20]

instead of more noisy:

chain(iota(5), filter!q{a}([1,0,3]))
chain(map!abs([1,2,-5]), [10, 20])

See also bug 5638 for a useful optimization.

I'd be glad to work on Phobos PR for this :)

Re: Chainable template mixin and opCat()

[via Digitalmars-d]

On Monday, 1 June 2015 at 12:13:51 UTC, Per Nordlöw wrote:

I still think the simplicity of

mixin Chainable;

and it's effect on usability is short enough to be worth the 
effort :)


https://github.com/D-Programming-Language/phobos/pull/3353

Destroy!

Re: Chainable template mixin and opCat()

[Timon Gehr via Digitalmars-d]

On 06/01/2015 01:47 PM, w0rp wrote:

you can't write operators as free functions. (Which is a good feature in
general.)


No, it is a pointless non-uniformity in function call syntax.