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digitalmars.D - Implicitly set template variables in D!

reply Nick <Nick_member pathlink.com> writes:
Yep! It's actually possible, but it isn't pretty :)

I've made a short example below. You have to use mixins to call the functions,
and give the function parameters as template parameters. For the moment, though,
you have to instantiate the templates explicitly somewhere else in the code, or
you get a linking error. But this is a compiler bug and will likely be fixed in
the future.

Also, you can't return values this way, but you can use as many inouts as you
want :)

PS: This is ment as a fun hack, not as a 'serious' solution to the template
problem. Enjoy!
Aug 05 2004
parent reply Sean Kelly <sean f4.ca> writes:
In article <cetqlb$1scn$1 digitaldaemon.com>, Nick says...

Yep! It's actually possible, but it isn't pretty :)


Very clever :)  I did manage to shave down your example a bit here:





















It has some weird limitations though.  The function has to return something,
since it's not possible to assign void to something and a template can't contain
just a statement.  Also, as you say it has to be a mixin otherwise there is the
message: "cannot use local 'x' as template parameter."  And getting the return
value is kind of a pain.  I can see how this could be extended to do some nifty
things, but it seems a lot of hoops to jump through in order to get around
typing "Print!(typeof(x))(x);"  Still, I'm going to play around with this some
more later and see what else this little trick can accomplish :)


Sean
Aug 05 2004
parent Nick <Nick_member pathlink.com> writes:
In article <cettal$1tu4$1 digitaldaemon.com>, Sean Kelly says...










Nice! But specifying the 'int' sort of takes the point away, though. You
probably meant it only to affect the return value type, but now it also sets the
parameter type. If you want these to always be the same, you could get away with




Nick
Aug 06 2004