• Eldar Insafutdinov <e.insafutdinov gmail.com> Jul 12 2009
• bearophile <bearophileHUGS lycos.com> Jul 12 2009
• Bill Baxter <wbaxter gmail.com> Jul 12 2009
• Daniel Keep <daniel.keep.lists gmail.com> Jul 12 2009

Eldar Insafutdinov <e.insafutdinov gmail.com> writes:

I am a little bit confused with a simple operation of searching in the array
with D2-phobos. With tango I used to use:
    size_t find( Elem[] buf, Elem pat, Pred2E pred = Pred2E.init );

    Performs a linear scan of buf from [0 .. buf.length), returning the index
of the first element matching pat, or buf.length if no match was found.
Comparisons will be performed using the supplied predicate or '==' if none is
supplied.

I tried std.algorithm.find:

class Node { ... }

Node[] v;
Node node;
...
int pos = find(v, node);

I get this error: /home/eldar/d/bin/../src/phobos/std/algorithm.d(1617): Error:
no property 'empty' for type 'model_d2.Node'

I think I completely misunderstood how to use it.

Many thanks in advance,
Eldar.

bearophile <bearophileHUGS lycos.com> writes:

Eldar Insafutdinov:
 I think I completely misunderstood how to use it.


Yes, it's too much complex. It tries to do many different things in the most
efficient way possible, the result is a high complexity in usage. That's one of
the faults of Andrei's code, it's not tested by letting  average coders use it.
A solution for this problem is to offer simple functions (like you can find in
Tango. In my dlibs the situation is intermediate, I think) with a simple API
for the most common purposes.

Bye,
bearophile

Bill Baxter <wbaxter gmail.com> writes:

On Sun, Jul 12, 2009 at 3:56 PM, bearophile<bearophileHUGS lycos.com> wrote=
:
 Eldar Insafutdinov:
 I think I completely misunderstood how to use it.


 Yes, it's too much complex. It tries to do many different things in the m=


s one of the faults of Andrei's code, it's not tested by letting =A0average=
 coders use it.
 A solution for this problem is to offer simple functions (like you can fi=


ple API for the most common purposes.

Isn't that a matter of built-in arrays not yet sporting the range interface=
?
I assume if .empty is part of the range interface then arrays are
supposed to support it.

--bb

Daniel Keep <daniel.keep.lists gmail.com> writes:

bearophile wrote:
 Eldar Insafutdinov:
 I think I completely misunderstood how to use it.


 Yes, it's too much complex. It tries to do many different things in the most
efficient way possible, the result is a high complexity in usage. That's one of
the faults of Andrei's code, it's not tested by letting  average coders use it.
 A solution for this problem is to offer simple functions (like you can find in
Tango. In my dlibs the situation is intermediate, I think) with a simple API
for the most common purposes.
 
 Bye,
 bearophile


It should work.  Taken from the algorithm docs:

 Example:

 int[] a = [ 1, 4, 2, 3 ];
 assert(find(a, 4) == [ 4, 2, 3 ]);




That said, find is too complex for his purposes.  Amazingly, Phobos
still appears to lack a basic indexOf function.

Phobos2: can build a working sentient AI that can feel love up from
individual atoms, but can't find the index of an array element.  :P