Re: Very simple null reference escape
On Sunday, 2 June 2019 at 07:55:27 UTC, Amex wrote:
A.B
If A is null, crash.
A?.B : writeln("HAHA");
No crash, ignored, equivalent to
if (A is null) writeln("HAHA"); else A.B;
safeAccess from iz does this :
https://github.com/Basile-z/iz/blob/master/import/iz/sugar.d#L1666
Re: Very simple null reference escape
On Sunday, 2 June 2019 at 14:37:48 UTC, Paul Backus wrote:
On Sunday, 2 June 2019 at 07:55:27 UTC, Amex wrote:
A.B
If A is null, crash.
A?.B : writeln("HAHA");
No crash, ignored, equivalent to
if (A is null) writeln("HAHA"); else A.B;
The "optional" package on dub [1] has a .dispatch method that
does this:
auto d = some(A());
// Dispatch to one of its methods
d.dispatch.f(); // calls a.f, returns some(4)
d.dispatch.inner.g(); // calls a.inner.g, returns some(7)
// Use on a pointer or reference type as well
A* e = null;
// If there's no value in the reference type, dispatching
// works, and produces an optional
assert(e.dispatch.f() == none);
assert(e.dispatch.inner.g() == none);
Full example: https://run.dlang.io/is/SmsGQu
[1] https://code.dlang.org/packages/optional
thanks.
Re: Very simple null reference escape
On Sunday, 2 June 2019 at 07:55:27 UTC, Amex wrote:
A.B
If A is null, crash.
A?.B : writeln("HAHA");
No crash, ignored, equivalent to
if (A is null) writeln("HAHA"); else A.B;
The "optional" package on dub [1] has a .dispatch method that
does this:
auto d = some(A());
// Dispatch to one of its methods
d.dispatch.f(); // calls a.f, returns some(4)
d.dispatch.inner.g(); // calls a.inner.g, returns some(7)
// Use on a pointer or reference type as well
A* e = null;
// If there's no value in the reference type, dispatching
// works, and produces an optional
assert(e.dispatch.f() == none);
assert(e.dispatch.inner.g() == none);
Full example: https://run.dlang.io/is/SmsGQu
[1] https://code.dlang.org/packages/optional
Very simple null reference escape
A.B
If A is null, crash.
A?.B : writeln("HAHA");
No crash, ignored, equivalent to
if (A is null) writeln("HAHA"); else A.B;
