bearophile wrote:
I've seen this change: http://dsource.org/projects/dmd/changeset/388
!in is one of the things I have asked in the first list of requests I
have posted in this newsgroup a lot of time ago :-) Glad to see few
of those things get implemented. Thank you.
The related thing I was asking for, is to use "in" for a linear
search of single items inside an array, as in Python, a very handy
thing that's used frequently (CPython it also implements an efficient
algorithm to search for a substring:
http://effbot.org/zone/stringlib.htm But probably Andrei wants such
substring search to be a separated algorithm, even if it's very
specifically tuned for strings only and not for arrays in general. I
can understand this).
That algorithm is nice. Generally I'd be hesitant to make it all too
easy to do linear searches. Too much of that would encourage people to
stick with linear searches because it's the path of least resistance.
Searching a value in a literal should actually be allowed:
x in [10, 20, 30, 0]
is great because the compiler has complete discretion in how to conduct
the search (e.g. linear vs. binary vs. hash search; it can take the
initiative of presorting the literal). But general search in an
unstructured range... maybe not.
That being said, the CPython string you pointed me to looks very
interesting. Phobos has a Boyer-Moore search implementation, but, just
like Fredrik Lundh, I'm unhappy that it does a fair amount of
computation upfront and that it needs dynamic allocation.
If someone has the time, please contribute a better implementation of
find() in std.algorithm.
Andrei
