Mixin Expressions, can't evalutate string variable

[Jacob Carlborg]

On 2010-08-05 23:50, Andrej Mitrovic wrote:
> On Thu, Aug 5, 2010 at 11:29 PM, Philippe Sigaud
> <philippe.sigaud at gmail.com <mailto:philippe.sigaud at gmail.com>> wrote:
>
>
>
>     On Thu, Aug 5, 2010 at 22:24, Andrej Mitrovic
>     <andrej.mitrovich at gmail.com <mailto:andrej.mitrovich at gmail.com>> wrote:
>
>         Thanks, Steven!
>
>         You don't want to know what I'm up to :p.
>
>
>     Yes, yes, wo do!
>
>
>         I'm using some traits to find out what kind of parameters a
>         function takes. I'm also using a demangler from phobos to find
>         out the name of the function (But I can't find any
>         straightforward way to get a name of a function without getting
>         back "1D_5std_5funcName" etc, so I just take a hardcoded slice).
>
>
>     You can get the name of an alias using __traits(identifier,
>     aliasName), like this for example:
>
>     template Name(alias a)
>     {
>        enum string Name = __traits(identifier, a);
>     }
>
>     int foo(int i) { return 0;}
>
>     import std.stdio;
>     void main()
>     {
>        writeln(Name!foo); // "foo", not "a".
>     }
>
>
>     As for demangling, how do you do to get mangled names in the first
>     place?
>
>
> I was using mangledName!() from std.straits. __traits works prefectly,
> Thanks!

You know there is a .mangleof property for all symbols.

>         Anyway, I have a template function which takes as it's
>         parameters a function (aliased to func), and some arguments
>         (right now just one in my hardcoded code). It then creates a
>         string which can be compiled via the mixin. It constructs the
>         string by checking the parameter types of func, and for any ref
>         or out parameter it detects it appends something like this to a
>         string:
>         "long var1; long var2; long var3; ".
>
>
>     How can you know if a parameter is ref or out?
>     I remember seeing something about it in Phobos svn, are you using it?
>
>
> Not svn, it's in 2.047 (maybe in earlier ones as well) in std.traits:
>
> ParameterTypeTuple!(alias) - for the types
> ParameterStorageClassTuple!(alias) - for the storage class
>
>         So anyway, at the calling site I have this:
>
>         mixin(unpack!(getTimes)(r"C:\\cookies"));
>
>         getTimes() is a Phobos function with the signature:
>         getTimes(in char[] name, out d_time ftc, out d_time fta, out
>         d_time ftm)
>
>         And now I automatically have var1, var2, and var3 at my disposal.
>
>
>     That's fun :)
>
>
>         It was just an exercise for fun but it's cool that things like
>         this are possible in D. It would be nice if I could get the
>         actual names of the parameters the function takes + the clear
>         name of the function itself, that way I'd actually get back
>         variables "ftc, fta, ftm" back)
>
>
>     I'm pretty sure I saw some code to do this. But maybe that was a D1
>     thing, using mangled names, too.
>     in dsource/scrapple?
>
>     Philippe
>
>
> Dunno, I haven't been using D1 really (actually I tried it some years
> ago with Tango but it left me wanting more so I never stuck around
> much). But D2 is super-fun.
>
>
>


-- 
/Jacob Carlborg