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digitalmars.D.bugs - [Issue 6043] New: Chainable template mixin

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6043

           Summary: Chainable template mixin
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc



I suggest to add something like this to D2 Phobos (this is D1 code):

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


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 an useful optimization.

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parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=6043


Andrej Mitrovic <andrej.mitrovich gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |andrej.mitrovich gmail.com



18:18:20 PST ---
Very interesting idea!

In fact, it's a bit odd that we allow the generally slow array appends (due to
allocations, reallocations, etc), but we use functions for chaining ranges.

I wonder if Andrei would approve this. Maybe you should bring this up to the
newsgroups for better awareness.

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