From: "nobu (Nobuyoshi Nakada)" Date: 2021-12-06T14:54:24+00:00 Subject: [ruby-core:106516] [Ruby master Feature#18033] Time.new to parse a string Issue #18033 has been updated by nobu (Nobuyoshi Nakada). Eregon (Benoit Daloze) wrote in #note-21: > Why we do we need to parse `Time#inspect` output? > It seems in general bad to rely on `inspect` for serialization, since it only works for some classes. > Maybe to preserve subseconds? I wrote `Time#inspect`, but the "ISO 8601-like" format is not only used by it, e.g., `--date=iso` of git. > `#inspect` does not feel like a proper way to serialize a Time instance, so if we want to add that I think we should have a new method for it too (maybe `#dump`?). > In any case, `Time.new` accepts individual time components, and I think making it parse strings is just confusing. How about `Time.at`? > A new method `Time.try_convert` (or `Time.undump`) feels more appropriate for such parsing. `Time.try_convert` feels considerable, but passing the timezone option may not fit. > > Second, ISO-8601 allows many variants, but I'm not going to implement them all. > > Is that what makes it faster? Not to be faster. ISO-8601 is a large specification and allows many omissions, which makes parsing very complex and sometimes conflicts with the spec of `Time`. > The PR still uses a Regexp so I guess the main difference is the Regexp is a little bit simpler? > They look fairly similar: > * https://github.com/ruby/ruby/pull/4639/files That PR is abandoned, please see [Time.new-string] or [Time.at-string]. [Time.new-string]: https://github.com/ruby/ruby/pull/4825 [Time.at-string]: https://github.com/ruby/ruby/pull/5212 ---------------------------------------- Feature #18033: Time.new to parse a string https://bugs.ruby-lang.org/issues/18033#change-95177 * Author: nobu (Nobuyoshi Nakada) * Status: Open * Priority: Normal ---------------------------------------- Make `Time.new` parse `Time#inspect` and ISO-8601 like strings. * `Time.iso8601` and `Time.parse` need an extension library, `date`. * `Time.iso8601` can't parse `Time#inspect` string. * `Time.parse` often results in unintentional/surprising results. * `Time.new` also about 1.9 times faster than `Time.iso8601`. ``` $ ./ruby -rtime -rbenchmark -e ' n = 1000 s = Time.now.iso8601 Benchmark.bm(12) do |x| x.report("Time.iso8601") {n.times{Time.iso8601(s)}} x.report("Time.parse") {n.times{Time.parse(s)}} x.report("Time.new") {n.times{Time.new(s)}} end' user system total real Time.iso8601 0.006919 0.000185 0.007104 ( 0.007091) Time.parse 0.018338 0.000207 0.018545 ( 0.018590) Time.new 0.003671 0.000069 0.003740 ( 0.003741) ``` https://github.com/ruby/ruby/pull/4639 -- https://bugs.ruby-lang.org/ Unsubscribe: