Thread overview
[Issue 3070] New: Implicitly conversion on function call
Jun 15, 2009
Robert Fraser
Jun 10, 2011
yebblies
June 15, 2009
http://d.puremagic.com/issues/show_bug.cgi?id=3070

           Summary: Implicitly conversion on function call
           Product: D
           Version: 2.030
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Severity: trivial
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: k0l0b0k.void@gmail.com


I have next pieces of code:

struct MyString
{
    public MyString opAssign(string pStr)
    {
        throw new Error("");
    }

    public MyString opCast(string pStr)
    {
        throw new Error("");
    }

    public MyString opImplicitCast(string pStr)
    {
        throw new Error("");
    }

    this(string pStr)
    {
        throw new Error("");
    }
}

void foo(MyString pStr)
{
}

int main(char[][] args)
{
    MyString str = "test1";
    str = "test2";
    foo(str);
    foo("test3");        // error "Error: cannot implicitly convert expression
("test3") of type immutable(char)[] to MyString
    return 0;
}


This is just sample. So, my trouble is to pass string argument to foo() with implicit conversion to MyString struct (I also tried class, with no results). I'm googled by this topic, but nothing found. Can you help me? This is not a bug (I think), but the question - how I can implicitly convert from one object to another in the as C++ does (C++ will call constructor with parameter type "string"). How I can make same in D?

Thanks in advance!

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
June 15, 2009
d-bugmail@puremagic.com wrote:
> http://d.puremagic.com/issues/show_bug.cgi?id=3070
> 
>            Summary: Implicitly conversion on function call
>            Product: D
>            Version: 2.030
>           Platform: x86
>         OS/Version: Windows
>             Status: NEW
>           Severity: trivial
>           Priority: P2
>          Component: DMD
>         AssignedTo: nobody@puremagic.com
>         ReportedBy: k0l0b0k.void@gmail.com
> 
> 
> I have next pieces of code:
> 
> struct MyString
> {
>     public MyString opAssign(string pStr)
>     {
>         throw new Error("");
>     }
> 
>     public MyString opCast(string pStr)
>     {
>         throw new Error("");
>     }
> 
>     public MyString opImplicitCast(string pStr)
>     {
>         throw new Error("");
>     }
> 
>     this(string pStr)
>     {
>         throw new Error("");
>     }
> }
> 
> void foo(MyString pStr)
> {
> }
> 
> int main(char[][] args)
> {
>     MyString str = "test1";
>     str = "test2";
>     foo(str);
>     foo("test3");        // error "Error: cannot implicitly convert expression
> ("test3") of type immutable(char)[] to MyString
>     return 0;
> }
> 
> 
> This is just sample. So, my trouble is to pass string argument to foo() with
> implicit conversion to MyString struct (I also tried class, with no results).
> I'm googled by this topic, but nothing found. Can you help me? This is not a
> bug (I think), but the question - how I can implicitly convert from one object
> to another in the as C++ does (C++ will call constructor with parameter type
> "string"). How I can make same in D?
> 
> Thanks in advance!
> 

If you want quicker responses to questions, try the newsgroups or IRC. Bugzilla is usually for bugs :-). Anyway, user-defined implicit casting is not implemented in (any version of) D yet. Sorry!
June 10, 2011
http://d.puremagic.com/issues/show_bug.cgi?id=3070


yebblies <yebblies@gmail.com> changed:

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


--- Comment #1 from yebblies <yebblies@gmail.com> 2011-06-10 10:31:11 PDT ---
Not a bug, works as designed.  D does not allow implicit casting like this.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------