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Remove str::is_whitespace and str::is_alphanumeric #49657
Description
These methods were added as stable in #49381 (currently in beta for 1.27.0) but we would prefer not to add them as discussed in #49381 (comment).
These methods were added as stable in #49381 (currently in beta for 1.27.0) but we would prefer not to add them as discussed in #49381 (comment).
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withoutboats commentedon Apr 4, 2018
Strongly prefer to have this method (unsurprisngly). I assumed it was an oversight that it was missing; I've probably tried
s.is_whitespace()a half dozen times and then been surprised it was nightly only.oli-obk commentedon Apr 5, 2018
We could add a system to be able to add suggestions to missing method errors. Thus the use of
is_whitespacewould suggest.chars().all(char::is_whitespace)Deleting these methods should of course not be blocked on such a system being in place
LukasKalbertodt commentedon Apr 5, 2018
@oli-obk I like this idea a lot! (independently from this discussion)
About
is_alphanumeric: I think I prefer to removestr::is_alphanumericas it might lead to subtle Unicode bugs. Example:The second string uses a Combining Diaeresis with an
oinstead of anö. Sure, the explicit variantchars().all(...)also has this problem, but being explicit makes the bug a bit less subtle. Havingis_alphanumericon a string might suggest that the method "does the right thing" (whatever that is) instead of looking at characters individually.I think
str::is_whitespacedoesn't have a problem with subtle Unicode bugs, but I don't quite like the name:is_whitespacesounds singular to me and thus doesn't translate perfectly to a string.If you are interested, I did a bit of research how
.chars().all(char::is_whitespace)is called in other languages (sometimes with libraries):blank?StringUtils.isBlankisspaceIsNullOrWhiteSpaceMaybe
str::is_blankis a better name for Rust?Auto merge of #50088 - alexcrichton:std-tweaks, r=sfackler