digitalmars.D.learn - Choosing between __traits(compiles, { ... } ) and is(typeof( { ... }
- =?UTF-8?B?Tm9yZGzDtnc=?= (9/9) Sep 20 2017 When is
- Stefan Koch (6/16) Sep 20 2017 Yes there are.
- =?UTF-8?B?Tm9yZGzDtnc=?= (6/9) Sep 20 2017 1. Can you give example of such visibility checks?
When is __traits(compiles, { ... } ) preferred over is(typeof( { ... } )) and vice versa when writing stuff like enum isCopyable(S) = is(typeof( { S foo = S.init; S copy = foo; } )); ? Further, are there cases where the two idioms aren't exchangable?
Sep 20 2017
On Wednesday, 20 September 2017 at 12:01:21 UTC, Nordlöw wrote:When is __traits(compiles, { ... } ) preferred over is(typeof( { ... } )) and vice versa when writing stuff like enum isCopyable(S) = is(typeof( { S foo = S.init; S copy = foo; } )); ? Further, are there cases where the two idioms aren't exchangable?Yes there are. Prefer __traits(compiles) it includes stricter visibility checks then is() does. Also compiles does not require the expression to resolve to a type.
Sep 20 2017
On Wednesday, 20 September 2017 at 12:20:18 UTC, Stefan Koch wrote:Yes there are. Prefer __traits(compiles) it includes stricter visibility checks then is() does.1. Can you give example of such visibility checks? 2. If so, should `isCopyable` (along with more defs in std.traits) be converted to instead use `__traits(compiles, )` ? 3. And how do the two idioms differ in terms of compilation-speed?
Sep 20 2017