On 11/2/16 11:17 AM, Adam D. Ruppe wrote:
On Wednesday, 2 November 2016 at 14:21:32 UTC, Shachar Shemesh wrote:
The D documentation (https://dlang.org/spec/hash-map.html) leaves this
not defined.
The foreach statement is defined to not allow it:
http://dlang.org/spec/statement.html#ForeachStatement
"The aggregate must be loop invariant, meaning that elements to the
aggregate cannot be added or removed from it in the
NoScopeNonEmptyStatement."
That's only for builtins. Obviously, there are cases where it can work,
and it needs to be defined by the aggregate/range. I think the
documentation should be updated to reflect that.
To answer the original question, it's not valid with the current
implementation AFAIK. I don't think we should define ever that it is
valid, even if we have an implementation that supports it, as this
restricts our implementation to always supporting it.
I'll point at my dcollections library as an example where the currently
iterated value can be removed:
https://github.com/schveiguy/dcollections/blob/master/concepts.txt#L81
I think Java also allows this, and C++ allows this.
-Steve
