On Monday, 3 November 2014 at 21:03:51 UTC, bioinfornatics wrote:
On Monday, 3 November 2014 at 06:43:50 UTC, Ali Çehreli wrote:
On 11/02/2014 04:58 PM, bioinfornatics wrote:
> Dear,
> Some problem to build this code:
http://fpaste.org/147327/75948141/
>
>
> $ ldc2 fasta_test.d
> /usr/include/d/std/range.d(3605): Error: template
std.array.save
> cannot deduce function from argument types !()(ByChunk),
> candidates are:
I think that is due to the too permissive template constraint
of takeOne in phobos/std/range.d. Even though it say
"isInputRange!R", it clearly needs "isForwardRange!R" because
it calls .save() on that range:
@property auto save() { return Result(_source.save, empty);
}
So, the following is wrong:
auto takeOne(R)(R source) if (isInputRange!R)
It should be:
auto takeOne(R)(R source) if (isForwardRange!R)
If you modify range.d locally to require ForwardRange, you
will see that your following call will get an error message
because byChunk is not a ForwardRange:
// Take a piece of byte from current file
ubyte[] buffer = takeOne(inputRange);
I think this issue is already reported as a part of the
following bug:
https://issues.dlang.org/show_bug.cgi?id=9724
Ali
Ok but I do not see why to use save method for a takeOne
function
is possible to write this function without to use it
Example:
auto takeOne(R)(ref R source) if (isInputRange!R)
{
static if (hasSlicing!R)
{
return source[0 .. !source.empty];
}
else
{
typeof(R.front) r;
if(!source.empty){
r = source.front;
source.popFront();
}
return r;
}
}
