Why ByChunk is not regnize by st.range.takeOne and why Section has no value

[Ali Çehreli via Digitalmars-d-learn]

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