[Issue 8715] map, filter, zip, not with functional arrays/associative arrays

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=8715


bearophile_hugs at eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|map, filter, zip with       |map, filter, zip, not with
                   |functional                  |functional
                   |arrays/associative arrays   |arrays/associative arrays


--- Comment #6 from bearophile_hugs at eml.cc 2012-12-30 18:14:53 PST ---
Two more examples:


import std.algorithm: filter;
import std.functional: not;
void main() {
    bool[] bad = [true, true, false, false, true, false];
    auto items = [0, 1, 2, 3, 4, 5];
    auto r1 = items.filter!bad();
    auto r2 = items.filter!(not!bad)();
}


...\dmd2\src\phobos\std\algorithm.d(1226): Error: function expected before (),
not bad of type bool[]
...\dmd2\src\phobos\std\algorithm.d(1248): Error: function expected before (),
not bad of type bool[]
...\dmd2\src\phobos\std\algorithm.d(1214): Error: template instance
test.main.FilterResult!(bad, int[]) error instantiating
test.d(6):        instantiated from here: filter!(int[])
test.d(6): Error: template instance test.main.filter!(bad).filter!(int[]) error
instantiating
...\dmd2\src\phobos\std\algorithm.d(1226): Error: template
test.main.not!(bad).not does not match any function template declaration.
Candidates are:
...\dmd2\src\phobos\std\functional.d(184):       
test.main.not!(bad).not(T...)(T args) if (is(typeof(!unaryFun!(pred)(args))) ||
is(typeof(!binaryFun!(pred)(args))))
...\dmd2\src\phobos\std\algorithm.d(1226): Error: template
test.main.not!(bad).not(T...)(T args) if (is(typeof(!unaryFun!(pred)(args))) ||
is(typeof(!binaryFun!(pred)(args)))) cannot deduce template function from
argument types !()(int)
...\dmd2\src\phobos\std\algorithm.d(1248): Error: template
test.main.not!(bad).not does not match any function template declaration.
Candidates are:
...\dmd2\src\phobos\std\functional.d(184):       
test.main.not!(bad).not(T...)(T args) if (is(typeof(!unaryFun!(pred)(args))) ||
is(typeof(!binaryFun!(pred)(args))))
...\dmd2\src\phobos\std\algorithm.d(1248): Error: template
test.main.not!(bad).not(T...)(T args) if (is(typeof(!unaryFun!(pred)(args))) ||
is(typeof(!binaryFun!(pred)(args)))) cannot deduce template function from
argument types !()(int)
...\dmd2\src\phobos\std\algorithm.d(1214): Error: template instance
std.algorithm.FilterResult!(not, int[]) error instantiating
test.d(7):        instantiated from here: filter!(int[])
test.d(7): Error: template instance std.algorithm.filter!(not).filter!(int[])
error instantiating

- - - - - - - - - - - - - - - -

import std.algorithm: filter;
struct IsOdd {
    static bool opCall(in int n) {
        return n % 2 == 1;
    }
}
void main() {
    auto items = [0, 1, 2, 3, 4, 5, 6, 7, 8];
    auto r1 = items.filter!(i => IsOdd(i))(); // OK
    auto r2 = items.filter!IsOdd(); // Error.
}


test.d(10): Error: template instance filter!(IsOdd) filter!(IsOdd) does not
match template declaration filter(alias pred) if (is(typeof(unaryFun!(pred))))

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