That is sensible. However, another way to look at it is:
1. "alias this" implements subtyping
2. By using "alias this" with string, DirEntry is subtyping the string type
3. A subtype of a range should be a range
Therefore, DirEntry is a range so the language needs to figure how to
treat it as such.
To some extent I'm playing devil's advocate because I foresee the
difficulties in making this work.
Andrei
On 10/26/15 5:27 PM, Walter Bright via phobos wrote:
On 10/26/2015 9:27 AM, Dmitry Olshansky via phobos wrote:
Agreed. That is my opinion as well, however luck of any attention from
you and Walter led to the point where we
need (a) and (b) to work right now and we hacked it (somewhat of
speaking for the community here, correct me if I'm wrong).
My recommendation was to remove the alias this in DirEntry that tried to
turn it into a string. A DirEntry is not a wrapper for a string, in
particular, it does not support range primitives, which is why the
string functions failed when changed to have InputRange parameters.
Adding range primitives to DirEntry would cause other weird problems,
because DirEntry is fundamentally not a range (a range 'consumes' its
data via popFront() which makes no sense for DirEntry).
Yes, that breaks:
DirEntry direntry;
remove(direntry);
which must be rewritten as:
DirEntry direntry;
remove(direntry.name);
and we're not supposed to break existing code. But the alternative,
which is redoing every template that accepts an InputRange, seems an
awfully heavy burden. Even if we do this change pervasively in Phobos,
how does that help anyone else who uses InputRanges?
Tl,dr: the alias this in DirEntry is an abusive bad practice, and should
never have happened.
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