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digitalmars.D.bugs - [Issue 10875] New: Introduce functionLinkageType to mirror functionLinkage with an enum

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10875

           Summary: Introduce functionLinkageType to mirror
                    functionLinkage with an enum
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: andrej.mitrovich gmail.com



04:51:27 PDT ---
Currently std.traits.functionLinkage returns the linkage type, but it returns
it as a string. So if you have generic code, you might end up writing code like
so:

-----
import std.traits;

extern(C) void func()
{
}

void main()
{
    enum linkage = functionLinkage!func;

    static if (linkage == "c")
    {
    }
    else
    static if (linkage == "D")
    {
    }
}
-----

Unfortunately there's a bug here, there is no lowercase "c" linkage type, only
"C". It would be safer if functionLinkage returned an enum. 

But since it's too late to change the return type, I propose we introduce an
enum version:

-----
import std.traits;

extern(C) void func()
{
}

void main()
{
    // new trait which returns a LinkageType enum instance
    enum linkage = functionLinkageType!func;

    static if (linkage == LinkageType.c)
    {
    }
    else
    static if (linkage == LinkageType.d)
    {
    }
}
-----

This will also allow a user to generate code by using EnumMembers on the
LinkageType enum.

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next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=10875




04:54:39 PDT ---


 But since it's too late to change the return type, I propose we introduce an
 enum version:


Actually a reasonable alternative is to simply introduce the LinkageType enum
which will have a string as its base type, so it can be used with the
functionLinkage function:

enum LinkageType : string
{
    D = "D",
    C = "C",
    Windows = "Windows",
    Pascal = "Pascal",
    Cpp = "C++"
}

-----
import std.traits;

extern(C) void func()
{
}

void main()
{
    enum linkage = functionLinkage!func;

    static if (linkage == LinkageType.C)
    {
    }
    else
    static if (linkage == LinkageType.D)
    {
    }
}
-----

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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bearophile_hugs eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bearophile_hugs eml.cc






 Actually a reasonable alternative is to simply introduce the LinkageType enum
 which will have a string as its base type, 


This is a nice idea to fix the original design mistake of using strings. Do you
know of other functions/templates in Phobos that could enjoy this the same
improvement?

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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09:22:04 PDT ---



 

 Actually a reasonable alternative is to simply introduce the LinkageType enum
 which will have a string as its base type, 


 
 This is a nice idea to fix the original design mistake of using strings. Do you
 know of other functions/templates in Phobos that could enjoy this the same
 improvement?


Nothing of the top of my head, but I think there are a few more.

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prev sibling parent d-bugmail puremagic.com writes:
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Andrej Mitrovic <andrej.mitrovich gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull
         AssignedTo|nobody puremagic.com        |andrej.mitrovich gmail.com



18:27:04 PDT ---
https://github.com/D-Programming-Language/phobos/pull/1587

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Sep 18 2013