On Wednesday, January 18, 2012 02:33:25 Jerome BENOIT wrote:
> And I cannot figure why :-(

http://d.puremagic.com/issues/show_bug.cgi?id=1528

As a workaround, templatize the last function by changing its signature to

int[] find()(int[] longer, int[] shorter)

- Jonathan M Davis

On 18/01/12 04:36, Jonathan M Davis wrote:
> On Wednesday, January 18, 2012 02:33:25 Jerome BENOIT wrote:
>> And I cannot figure why :-(
>
> http://d.puremagic.com/issues/show_bug.cgi?id=1528
>
> As a workaround, templatize the last function by changing its signature to
>
> int[] find()(int[] longer, int[] shorter)

actually it does not work either: gdmd gives an other error message now.

------------------------------------------------------------------------
T[] find(T, E)(T[] haystack, E needle)
	if (is(typeof(haystack[0] != needle) == bool)) {
	while (haystack.length > 0 && haystack[0] != needle) {
		haystack = haystack[1 .. $];
		}
	return haystack;
	}

TL[] find(TL, TS)(TL[] longer, TS[] shorter)
	if (is(typeof(longer[0 .. 1] == shorter) : bool)) {
	while (longer.length >= shorter.length) {
		if (longer[0 .. shorter.length] == shorter) break;
		longer=longer[1 .. $];
		}
	return longer;
	}

int[] find()(int[] longer, int[] shorter) {
	while (longer.length >= shorter.length) {
		if (longer[0 .. shorter.length] == shorter) break;
		longer=longer[1 .. $];
		}
	return longer;
	}

unittest {
	// Test the introduced overloads
	long[] a1 = [ 6, 1, 2, 3 ];
	long[] a2 = [ 1 , 2 ];
	int[] b1 = [ 6, 1, 2, 3 ];
	int[] b2 = [ 1 , 2 ];
	assert(find(a1, a2) == a1[1 .. $]);
	assert(find(a1, b2) == a1[1 .. $]);
	assert(find(b1, b2) == b1[1 .. $]);
	}

void main() {}
------------------------------------------------------------------------

The message is now:
searching_05.d:34: Error: template searching_05.find(T,E) if (is(typeof(haystack[0] != needle) == bool)) find(T,E) if (is(typeof(haystack[0] != needle) == bool)) matches more than one template declaration, searching_05.d(9):find(TL,TS) if (is(typeof(longer[0..1] == shorter) : bool)) and searching_05.d(18):find()

Is partial ordering really supported ?

Jerome



>
> - Jonathan M Davis

On 01/18/2012 02:32 PM, Jerome BENOIT wrote:
>
>
> On 18/01/12 04:36, Jonathan M Davis wrote:
>> On Wednesday, January 18, 2012 02:33:25 Jerome BENOIT wrote:
>>> And I cannot figure why :-(
>>
>> http://d.puremagic.com/issues/show_bug.cgi?id=1528
>>
>> As a workaround, templatize the last function by changing its
>> signature to
>>
>> int[] find()(int[] longer, int[] shorter)
>
> actually it does not work either: gdmd gives an other error message now.
>
> ------------------------------------------------------------------------
> T[] find(T, E)(T[] haystack, E needle)
> if (is(typeof(haystack[0] != needle) == bool)) {
> while (haystack.length > 0 && haystack[0] != needle) {
> haystack = haystack[1 .. $];
> }
> return haystack;
> }
>
> TL[] find(TL, TS)(TL[] longer, TS[] shorter)
> if (is(typeof(longer[0 .. 1] == shorter) : bool)) {
> while (longer.length >= shorter.length) {
> if (longer[0 .. shorter.length] == shorter) break;
> longer=longer[1 .. $];
> }
> return longer;
> }
>
> int[] find()(int[] longer, int[] shorter) {
> while (longer.length >= shorter.length) {
> if (longer[0 .. shorter.length] == shorter) break;
> longer=longer[1 .. $];
> }
> return longer;
> }
>
> unittest {
> // Test the introduced overloads
> long[] a1 = [ 6, 1, 2, 3 ];
> long[] a2 = [ 1 , 2 ];
> int[] b1 = [ 6, 1, 2, 3 ];
> int[] b2 = [ 1 , 2 ];
> assert(find(a1, a2) == a1[1 .. $]);
> assert(find(a1, b2) == a1[1 .. $]);
> assert(find(b1, b2) == b1[1 .. $]);
> }
>
> void main() {}
> ------------------------------------------------------------------------
>
> The message is now:
> searching_05.d:34: Error: template searching_05.find(T,E) if
> (is(typeof(haystack[0] != needle) == bool)) find(T,E) if
> (is(typeof(haystack[0] != needle) == bool)) matches more than one
> template declaration, searching_05.d(9):find(TL,TS) if
> (is(typeof(longer[0..1] == shorter) : bool)) and searching_05.d(18):find()
>
> Is partial ordering really supported ?
>

Yes it is, and your code snippet indeed compiles on my machine. Are you maybe using an outdated version of the compiler?

On 01/18/2012 04:57 PM, Timon Gehr wrote:
> On 01/18/2012 02:32 PM, Jerome BENOIT wrote:
>>
>>
>> On 18/01/12 04:36, Jonathan M Davis wrote:
>>> On Wednesday, January 18, 2012 02:33:25 Jerome BENOIT wrote:
>>>> And I cannot figure why :-(
>>>
>>> http://d.puremagic.com/issues/show_bug.cgi?id=1528
>>>
>>> As a workaround, templatize the last function by changing its
>>> signature to
>>>
>>> int[] find()(int[] longer, int[] shorter)
>>
>> actually it does not work either: gdmd gives an other error message now.
>>
>> ------------------------------------------------------------------------
>> T[] find(T, E)(T[] haystack, E needle)
>> if (is(typeof(haystack[0] != needle) == bool)) {
>> while (haystack.length > 0 && haystack[0] != needle) {
>> haystack = haystack[1 .. $];
>> }
>> return haystack;
>> }
>>
>> TL[] find(TL, TS)(TL[] longer, TS[] shorter)
>> if (is(typeof(longer[0 .. 1] == shorter) : bool)) {
>> while (longer.length >= shorter.length) {
>> if (longer[0 .. shorter.length] == shorter) break;
>> longer=longer[1 .. $];
>> }
>> return longer;
>> }
>>
>> int[] find()(int[] longer, int[] shorter) {
>> while (longer.length >= shorter.length) {
>> if (longer[0 .. shorter.length] == shorter) break;
>> longer=longer[1 .. $];
>> }
>> return longer;
>> }
>>
>> unittest {
>> // Test the introduced overloads
>> long[] a1 = [ 6, 1, 2, 3 ];
>> long[] a2 = [ 1 , 2 ];
>> int[] b1 = [ 6, 1, 2, 3 ];
>> int[] b2 = [ 1 , 2 ];
>> assert(find(a1, a2) == a1[1 .. $]);
>> assert(find(a1, b2) == a1[1 .. $]);
>> assert(find(b1, b2) == b1[1 .. $]);
>> }
>>
>> void main() {}
>> ------------------------------------------------------------------------
>>
>> The message is now:
>> searching_05.d:34: Error: template searching_05.find(T,E) if
>> (is(typeof(haystack[0] != needle) == bool)) find(T,E) if
>> (is(typeof(haystack[0] != needle) == bool)) matches more than one
>> template declaration, searching_05.d(9):find(TL,TS) if
>> (is(typeof(longer[0..1] == shorter) : bool)) and
>> searching_05.d(18):find()
>>
>> Is partial ordering really supported ?
>>
>
> Yes it is, and your code snippet indeed compiles on my machine. Are you
> maybe using an outdated version of the compiler?
>
>

Nevermind, I forgot to pass the -unittest switch. It indeed gives that error. The reason it still does not compile is that the workaround proposed by Jonathan has slightly different semantics than it would have if the compiler already supported overloading of functions against function templates.

If exactly one of two equally good matched functions is a templated one, the other one is chosen. Now that you have templated the second function, both are an equally good match and both are templated.

If you change the last signature to
int[] find(TL:int[], TS:int[])(TL longer, TS shorter)

It will compile. However, if TL or TS are user-defined types with an alias this of type int[], the semantics are still different. I think this bug needs special attention.

On 18/01/12 17:07, Timon Gehr wrote:
> On 01/18/2012 04:57 PM, Timon Gehr wrote:
>> On 01/18/2012 02:32 PM, Jerome BENOIT wrote:
>>>
>>>
>>> On 18/01/12 04:36, Jonathan M Davis wrote:
>>>> On Wednesday, January 18, 2012 02:33:25 Jerome BENOIT wrote:
>>>>> And I cannot figure why :-(
>>>>
>>>> http://d.puremagic.com/issues/show_bug.cgi?id=1528
>>>>
>>>> As a workaround, templatize the last function by changing its
>>>> signature to
>>>>
>>>> int[] find()(int[] longer, int[] shorter)
>>>
>>> actually it does not work either: gdmd gives an other error message now.
>>>
>>> ------------------------------------------------------------------------
>>> T[] find(T, E)(T[] haystack, E needle)
>>> if (is(typeof(haystack[0] != needle) == bool)) {
>>> while (haystack.length > 0 && haystack[0] != needle) {
>>> haystack = haystack[1 .. $];
>>> }
>>> return haystack;
>>> }
>>>
>>> TL[] find(TL, TS)(TL[] longer, TS[] shorter)
>>> if (is(typeof(longer[0 .. 1] == shorter) : bool)) {
>>> while (longer.length >= shorter.length) {
>>> if (longer[0 .. shorter.length] == shorter) break;
>>> longer=longer[1 .. $];
>>> }
>>> return longer;
>>> }
>>>
>>> int[] find()(int[] longer, int[] shorter) {
>>> while (longer.length >= shorter.length) {
>>> if (longer[0 .. shorter.length] == shorter) break;
>>> longer=longer[1 .. $];
>>> }
>>> return longer;
>>> }
>>>
>>> unittest {
>>> // Test the introduced overloads
>>> long[] a1 = [ 6, 1, 2, 3 ];
>>> long[] a2 = [ 1 , 2 ];
>>> int[] b1 = [ 6, 1, 2, 3 ];
>>> int[] b2 = [ 1 , 2 ];
>>> assert(find(a1, a2) == a1[1 .. $]);
>>> assert(find(a1, b2) == a1[1 .. $]);
>>> assert(find(b1, b2) == b1[1 .. $]);
>>> }
>>>
>>> void main() {}
>>> ------------------------------------------------------------------------
>>>
>>> The message is now:
>>> searching_05.d:34: Error: template searching_05.find(T,E) if
>>> (is(typeof(haystack[0] != needle) == bool)) find(T,E) if
>>> (is(typeof(haystack[0] != needle) == bool)) matches more than one
>>> template declaration, searching_05.d(9):find(TL,TS) if
>>> (is(typeof(longer[0..1] == shorter) : bool)) and
>>> searching_05.d(18):find()
>>>
>>> Is partial ordering really supported ?
>>>
>>
>> Yes it is, and your code snippet indeed compiles on my machine. Are you
>> maybe using an outdated version of the compiler?
>>
>>
>
> Nevermind, I forgot to pass the -unittest switch. It indeed gives that error. The reason it still does not compile is that the workaround proposed by Jonathan has slightly different semantics than it would have if the compiler already supported overloading of functions against function templates.
>
> If exactly one of two equally good matched functions is a templated one, the other one is chosen.

So the D code in my first post may work and thus the workaround is not necessary.

For information, I use gdc on a Debian Testing box.

 Now that you have templated the second function, both are an equally good match and both are templated.
>
> If you change the last signature to
> int[] find(TL:int[], TS:int[])(TL longer, TS shorter)
>
> It will compile. However, if TL or TS are user-defined types with an alias this of type int[], the semantics are still different. I think this bug needs special attention.
>
>
>
>
>

On 01/18/2012 05:40 PM, Jerome BENOIT wrote:
>
>
> On 18/01/12 17:07, Timon Gehr wrote:
>> On 01/18/2012 04:57 PM, Timon Gehr wrote:
>>> On 01/18/2012 02:32 PM, Jerome BENOIT wrote:
>>>>
>>>>
>>>> On 18/01/12 04:36, Jonathan M Davis wrote:
>>>>> On Wednesday, January 18, 2012 02:33:25 Jerome BENOIT wrote:
>>>>>> And I cannot figure why :-(
>>>>>
>>>>> http://d.puremagic.com/issues/show_bug.cgi?id=1528
>>>>>
>>>>> As a workaround, templatize the last function by changing its
>>>>> signature to
>>>>>
>>>>> int[] find()(int[] longer, int[] shorter)
>>>>
>>>> actually it does not work either: gdmd gives an other error message
>>>> now.
>>>>
>>>> ------------------------------------------------------------------------
>>>>
>>>> T[] find(T, E)(T[] haystack, E needle)
>>>> if (is(typeof(haystack[0] != needle) == bool)) {
>>>> while (haystack.length > 0 && haystack[0] != needle) {
>>>> haystack = haystack[1 .. $];
>>>> }
>>>> return haystack;
>>>> }
>>>>
>>>> TL[] find(TL, TS)(TL[] longer, TS[] shorter)
>>>> if (is(typeof(longer[0 .. 1] == shorter) : bool)) {
>>>> while (longer.length >= shorter.length) {
>>>> if (longer[0 .. shorter.length] == shorter) break;
>>>> longer=longer[1 .. $];
>>>> }
>>>> return longer;
>>>> }
>>>>
>>>> int[] find()(int[] longer, int[] shorter) {
>>>> while (longer.length >= shorter.length) {
>>>> if (longer[0 .. shorter.length] == shorter) break;
>>>> longer=longer[1 .. $];
>>>> }
>>>> return longer;
>>>> }
>>>>
>>>> unittest {
>>>> // Test the introduced overloads
>>>> long[] a1 = [ 6, 1, 2, 3 ];
>>>> long[] a2 = [ 1 , 2 ];
>>>> int[] b1 = [ 6, 1, 2, 3 ];
>>>> int[] b2 = [ 1 , 2 ];
>>>> assert(find(a1, a2) == a1[1 .. $]);
>>>> assert(find(a1, b2) == a1[1 .. $]);
>>>> assert(find(b1, b2) == b1[1 .. $]);
>>>> }
>>>>
>>>> void main() {}
>>>> ------------------------------------------------------------------------
>>>>
>>>>
>>>> The message is now:
>>>> searching_05.d:34: Error: template searching_05.find(T,E) if
>>>> (is(typeof(haystack[0] != needle) == bool)) find(T,E) if
>>>> (is(typeof(haystack[0] != needle) == bool)) matches more than one
>>>> template declaration, searching_05.d(9):find(TL,TS) if
>>>> (is(typeof(longer[0..1] == shorter) : bool)) and
>>>> searching_05.d(18):find()
>>>>
>>>> Is partial ordering really supported ?
>>>>
>>>
>>> Yes it is, and your code snippet indeed compiles on my machine. Are you
>>> maybe using an outdated version of the compiler?
>>>
>>>
>>
>> Nevermind, I forgot to pass the -unittest switch. It indeed gives that
>> error. The reason it still does not compile is that the workaround
>> proposed by Jonathan has slightly different semantics than it would
>> have if the compiler already supported overloading of functions
>> against function templates.
>>
>> If exactly one of two equally good matched functions is a templated
>> one, the other one is chosen.
>
> So the D code in my first post may work and thus the workaround is not
> necessary.
>

The language does not mandate the workaround, but the workaround is necessary until the compiler is fixed.

On 18/01/12 18:05, Timon Gehr wrote:
> On 01/18/2012 05:40 PM, Jerome BENOIT wrote:
>>
>>
>> On 18/01/12 17:07, Timon Gehr wrote:
>>> On 01/18/2012 04:57 PM, Timon Gehr wrote:
>>>> On 01/18/2012 02:32 PM, Jerome BENOIT wrote:
>>>>>
>>>>>
>>>>> On 18/01/12 04:36, Jonathan M Davis wrote:
>>>>>> On Wednesday, January 18, 2012 02:33:25 Jerome BENOIT wrote:
>>>>>>> And I cannot figure why :-(
>>>>>>
>>>>>> http://d.puremagic.com/issues/show_bug.cgi?id=1528
>>>>>>
>>>>>> As a workaround, templatize the last function by changing its
>>>>>> signature to
>>>>>>
>>>>>> int[] find()(int[] longer, int[] shorter)
>>>>>
>>>>> actually it does not work either: gdmd gives an other error message
>>>>> now.
>>>>>
>>>>> ------------------------------------------------------------------------
>>>>>
>>>>> T[] find(T, E)(T[] haystack, E needle)
>>>>> if (is(typeof(haystack[0] != needle) == bool)) {
>>>>> while (haystack.length > 0 && haystack[0] != needle) {
>>>>> haystack = haystack[1 .. $];
>>>>> }
>>>>> return haystack;
>>>>> }
>>>>>
>>>>> TL[] find(TL, TS)(TL[] longer, TS[] shorter)
>>>>> if (is(typeof(longer[0 .. 1] == shorter) : bool)) {
>>>>> while (longer.length >= shorter.length) {
>>>>> if (longer[0 .. shorter.length] == shorter) break;
>>>>> longer=longer[1 .. $];
>>>>> }
>>>>> return longer;
>>>>> }
>>>>>
>>>>> int[] find()(int[] longer, int[] shorter) {
>>>>> while (longer.length >= shorter.length) {
>>>>> if (longer[0 .. shorter.length] == shorter) break;
>>>>> longer=longer[1 .. $];
>>>>> }
>>>>> return longer;
>>>>> }
>>>>>
>>>>> unittest {
>>>>> // Test the introduced overloads
>>>>> long[] a1 = [ 6, 1, 2, 3 ];
>>>>> long[] a2 = [ 1 , 2 ];
>>>>> int[] b1 = [ 6, 1, 2, 3 ];
>>>>> int[] b2 = [ 1 , 2 ];
>>>>> assert(find(a1, a2) == a1[1 .. $]);
>>>>> assert(find(a1, b2) == a1[1 .. $]);
>>>>> assert(find(b1, b2) == b1[1 .. $]);
>>>>> }
>>>>>
>>>>> void main() {}
>>>>> ------------------------------------------------------------------------
>>>>>
>>>>>
>>>>> The message is now:
>>>>> searching_05.d:34: Error: template searching_05.find(T,E) if
>>>>> (is(typeof(haystack[0] != needle) == bool)) find(T,E) if
>>>>> (is(typeof(haystack[0] != needle) == bool)) matches more than one
>>>>> template declaration, searching_05.d(9):find(TL,TS) if
>>>>> (is(typeof(longer[0..1] == shorter) : bool)) and
>>>>> searching_05.d(18):find()
>>>>>
>>>>> Is partial ordering really supported ?
>>>>>
>>>>
>>>> Yes it is, and your code snippet indeed compiles on my machine. Are you
>>>> maybe using an outdated version of the compiler?
>>>>
>>>>
>>>
>>> Nevermind, I forgot to pass the -unittest switch. It indeed gives that
>>> error. The reason it still does not compile is that the workaround
>>> proposed by Jonathan has slightly different semantics than it would
>>> have if the compiler already supported overloading of functions
>>> against function templates.
>>>
>>> If exactly one of two equally good matched functions is a templated
>>> one, the other one is chosen.
>>
>> So the D code in my first post may work and thus the workaround is not
>> necessary.
>>
>
> The language does not mandate the workaround, but the workaround is necessary until the compiler is fixed.

Thanks for the precision. So I will move to the next section and come back to this part when the compiler is fix:
I guess it will be fixed for the next release as it sounds as an important bug.

Jerome

On Wednesday, January 18, 2012 21:35:44 Jerome BENOIT wrote:
> Thanks for the precision. So I will move to the next section and come back to this part when the compiler is fix: I guess it will be fixed for the next release as it sounds as an important bug.

I don't know. It's been a bug for a long time. However, there has been push recently to try and get the known bugs with regards to TDPL fixed, and this is definitely on the list. So, I would expect it to be fixed relatively soon, but it may not be fixed by the next release.

- Jonathan M Davis