From: "danh337 (Dan H)" Date: 2022-02-21T19:35:53+00:00 Subject: [ruby-core:107695] [Ruby master Feature#16295] Chainable aliases for String#-@ and String#+@ Issue #16295 has been updated by danh337 (Dan H). Eregon (Benoit Daloze) wrote in #note-7: > @danh337 `-@` and the proposed `dedup` intern/deduplicate. > This is the main feature of those methods and it is *very much* part of the semantics (as the docs say). > It's the whole point of these methods really, to reduce the number of duplicate strings and reduce memory usage (which @byroot and others successfully used in many gems). > > `freeze` does not intern/deduplicate. That has the advantage it's faster, but it doesn't help memory footprint if there are many duplicates of the same string. > > Regarding `+@`/`dup` feel free to continue discussing that on #16295, this issue should remain focused on `dedup`, that is the purpose of the new issue. The `.@+` is still not resolved, even though #16295 is closed. If the *behavior* of `.+@` and `.dup` is the same, that's fine and I get your point, but `x = "".dup` is semantically weird. I realize that `x = +""` is probably what most would use anyway, but for method chains that mutate a String, where I know the String is *expected* to mutate, a "fast" inverse of `.freeze` would be nice instead of always `.dup`. If a String is already mutable, we do not want to duplicate it. ---------------------------------------- Feature #16295: Chainable aliases for String#-@ and String#+@ https://bugs.ruby-lang.org/issues/16295#change-96613 * Author: byroot (Jean Boussier) * Status: Closed * Priority: Normal ---------------------------------------- Original discussion https://bugs.ruby-lang.org/issues/16150?next_issue_id=16147&prev_issue_id=16153#note-40 In #16150, @headius raised the following concern about `String#-@` and `String#+@`: headius (Charles Nutter) wrote: > > Not exactly, -@ and +@ makes this much simpler > > I do like the unary operators, but they also have some precedence oddities: > > ``` > >> -"foo".size > => -3 > >> (-"foo").size > => 3 > ``` > > And it doesn't work at all if you're chaining method calls: > > ``` > >> +ary.to_s.frozen? > NoMethodError: undefined method `+@' for false:FalseClass > from (irb):8 > from /usr/bin/irb:11:in `
' > ``` > > But you are right, instead of the explicit `dup` with possible freeze you could use `-` or `+` on the result of `to_s`. However it's still not safe to modify it since it would modify the original string too. After working for quite a while with those, I have to say I agree. They very often force to use parentheses, which is annoying, and an indication that regular methods would be preferable to unary operators. In response @matz proposed to alias them as `String#+` and `String#-` without arguments: > How about making String#+ and #- without argument behave like #+@ and #-@ respectively, so that we can write: > > ``` > "foo".-.size > ary.to_s.+.frozen? > ``` My personal opinion is that descriptive method names would be preferable to `+/-`: > IMHO `.-` and `.+` is not very elegant. Proper method names explaining the intent would be preferable. > > - `-@` could be `dedup`, or `deduplicate`. > - `+@` could be `mutable` or `mut`. -- https://bugs.ruby-lang.org/ Unsubscribe: