http://d.puremagic.com/issues/show_bug.cgi?id=11254

           Summary: std.string.strip is not nothrow
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: Phobos
        AssignedTo: nobody@puremagic.com
        ReportedBy: bearophile_hugs@eml.cc


--- Comment #0 from bearophile_hugs@eml.cc 2013-10-14 02:52:27 PDT ---
import std.string: strip;
void main() nothrow {
    " hello ".strip;
}



dmd 2.064beta gives:

test.d(3): Error: 'std.string.strip!(immutable(char)).strip' is not nothrow
test.d(2): Error: function 'D main' is nothrow yet may throw


I don't know if this can be done. Often string functions need to decode UTF, and this could raise exceptions. In most cases, or for ASCII strings, a strip can't throw exceptions.

If this can't be done then please close down this issue.

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monarchdodra@gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |monarchdodra@gmail.com
         Resolution|                            |INVALID


--- Comment #1 from monarchdodra@gmail.com 2013-10-14 05:55:11 PDT ---
(In reply to comment #0)
> import std.string: strip;
> void main() nothrow {
>     " hello ".strip;
> }
> 
> 
> 
> dmd 2.064beta gives:
> 
> test.d(3): Error: 'std.string.strip!(immutable(char)).strip' is not nothrow
> test.d(2): Error: function 'D main' is nothrow yet may throw
> 
> 
> I don't know if this can be done. Often string functions need to decode UTF, and this could raise exceptions. In most cases, or for ASCII strings, a strip can't throw exceptions.
> 
> If this can't be done then please close down this issue.

strip is a unicode aware function, that can remove unicode whites, so it *must* decode. So even if "most of the time", it won't throw, in the generic case, it can.

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--- Comment #2 from bearophile_hugs@eml.cc 2013-10-14 09:46:51 PDT ---
(In reply to comment #1)

> strip is a unicode aware function, that can remove unicode whites, so it *must* decode. So even if "most of the time", it won't throw, in the generic case, it can.

Some possible alternative solutions:
- A strip-like function that works on ubyte[] (the return type of
std.string.representation if you give it a string);
- A compile-time switch for std.string.strip that compiles out the
unicode-aware parts.
- A std.ascii.astrip nothrow function designed to work only on ASCII
strings/char[].

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--- Comment #3 from monarchdodra@gmail.com 2013-10-14 11:50:50 PDT ---
(In reply to comment #2)
> (In reply to comment #1)
> 
> > strip is a unicode aware function, that can remove unicode whites, so it *must* decode. So even if "most of the time", it won't throw, in the generic case, it can.
> 
> Some possible alternative solutions:
> - A strip-like function that works on ubyte[] (the return type of
> std.string.representation if you give it a string);
> - A compile-time switch for std.string.strip that compiles out the
> unicode-aware parts.
> - A std.ascii.astrip nothrow function designed to work only on ASCII
> strings/char[].

You should try the new generic std.algorithm.strip:

//----
import std.string, std.ascii, std.algorithm;

void main(string[] args) nothrow pure
{
    string s = " hello! ";
    s = cast(string)s.representation.strip!isWhite();
}
//----

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Jonathan M Davis <jmdavisProg@gmx.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jmdavisProg@gmx.com


--- Comment #4 from Jonathan M Davis <jmdavisProg@gmx.com> 2013-10-14 19:41:32 PDT ---
I think that we should probably move towards overloading string functions with ubyte[] so that they can have ASCII-specific versions, and more of those would be able to be nothrow.

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