3 ms·
I'd like to read more about this. It would be a little unfortunate to end up with Python's "x in y" and "del y[x]" just to differentiate between missing entries
by anonymoushn 6y ago
I'd like to read more about this. It would be a little unfortunate to end up with Python's "x in y" and "del y[x]" just to differentiate between missing entries and present entries set to nil.
On the other hand, my not-very-well-considered preferred approach creates some asymmetry between arrays and maps as to what values can be stored. Or it perpetuates the existing asymmetry between varargs and tables...
- pansa2 6y agoFrom http://lua-users.org/lists/lua-l/2018-03/msg00155.html http://lua-users.org/lists/lua-l/2018-03/msg00155.html. Looks like this was in the first pre-alpha release of 5.4 but removed shortly afterwards: > t[i]=undef is a special syntax form that means "remove the key 'i' from table 't'". You can only use 'undef' in three specific forms: t[i] = undef -- remove a key from a table t[i] == undef -- test whether a table has a key t[i] ~= undef -- test whether a table has a key
- anonymoushn 6y agoThanks! I like this proposal a lot.