On Friday, 26 April 2013 at 07:31:57 UTC, Trey Brisbane wrote:
Hey all,
Can someone please explain to me how and why it is that
toStringz() and toUTFz() can be used in the following way?
string a = "123";
auto b = a.toStringz;
auto c = a.toUTFz;
Also, how is it that they can even be called as if they were
class methods? That is:
string a = "123";
auto b = a.toStringz(); // <-- Note I've added parentheses
auto c = a.toUTFz();
As opposed to being limited to:
string a = "123";
auto b = toStringz(a);
auto c = toUTFz(a);
There's two things at work here:
a) Universal Function Call Syntax (UFCS). That basically means
that you can call a free function via method/property-like dot
syntax. The first argument to the function goes before the dot.
UFCS should be explained in the online language documentation,
but if it's in there I can't find it.
So, with UFCS you get from toStringz(a) to a.toStringz() .
b) Empty parentheses are optional. -- Unless you compile with the
-property flag. There has been some discussion about the future
of the feature. Optional empty parentheses and/or the -property
flag may go away in the future.
That gets you from a.toString() to a.toString .
I need to understand this, as I wish to write a function
toWinStr() that can be used in the same way which will accept
any string type, and, based on something like version(Unicode)
and const-ness, output a WinAPI LPSTR, LPCSTR, LPWSTR or
LPCWSTR as appropriate.
Is such a thing possible?
You just write your function so that toWinStr(stuff) works.
UFCS and optional empty parentheses then enable stuff.toWinStr .
