On Friday, 7 December 2012 at 14:21:51 UTC, Nick Treleaven wrote:
On 03/12/2012 14:22, Nick Treleaven wrote:
Most programmers would probably just pollute the existing
scope:
auto x = "thing" in arr;
if (x && *x == 45)
{
...
}
I expect this is because wrapping the above in {} for a new
scope is
just too ugly, introducing more nesting and indentation.
It would be nice if there was a way of introducing a new scope
just for
a declaration and the next statement, something like:
with auto x = "thing" in arr:
if (x && *x == 45)
{
// x is still visible here
}
That would overload 'with' with a different meaning, but would
be clear
enough IMO. It would be useful with other constructs like
while, do,
foreach, etc. I think it would be more elegant than allowing a
declaration clause in all constructs (like the 'for' statement
has).
The above syntax was inspired from Tove and Tommi's existing
solution (I couldn't find the link earlier):
http://forum.dlang.org/post/[email protected]
The idea was to use a Tuple to wrap the new variable:
with (Tuple!(int, "a")(getInt()))
if (a > 9)
...
I've now improved on this syntax using opDispatch and opAssign
so we can write:
with (wrap.a = getInt())
if (a > 9)
...
Whether using this in real code is good practice or not may be
debatable ;-)
Code:
http://dpaste.dzfl.pl/4dbefd84
That is really an interesting idea.
