On Thursday, 15 October 2015 at 18:07:24 UTC, Shriramana Sharma
wrote:
So, any thoughts? Any way this could be improved? Would be nice
if that mixin got into the standard library somehow...
Writing a mixin to create a standard constructor for exception
types is trivial. The problem is that you can't document code
that's mixed in. So, the constructors wouldn't end up in the
documentation. And while it's a bit annoying, copy-pasting the
two standard constructors for exceptions is pretty trivial.
/++
Params:
msg = The message for the exception.
file = The file where the exception occurred.
line = The line number where the exception occurred.
next = The previous exception in the chain of
exceptions, if any.
+/
this(string msg,
string file = __FILE__,
size_t line = __LINE__,
Throwable next = null) @safe pure nothrow
{
super(msg, file, line, next);
}
/++
Params:
msg = The message for the exception.
next = The previous exception in the chain of
exceptions.
file = The file where the exception occurred.
line = The line number where the exception occurred.
+/
this(string msg,
Throwable next,
string file = __FILE__,
size_t line = __LINE__) @safe pure nothrow
{
super(msg, file, line, next);
}
So, while this is annoying, I don't think that it's a huge
problem. We probably should have better documentation on it
though.
However, if we were ever to get ddoc support for mixins, then we
could easily write a function to use for mixing in the
constructors in exception types. Heck, for exceptions that just
have the two standard constructors, we could create a function to
provide the code to mix in the whole type declaration. e.g.
/++
My exception type.
+/
mixin(genExceptionType("MyException"));
But as long as you can't put ddoc on mixins or have the ddoc
inside a mixin end up in the documentation, we're pretty much out
of luck on that count.
- Jonathan M Davis
