From: shyouhei@... Date: 2016-12-08T10:16:18+00:00 Subject: [ruby-core:78546] [Ruby trunk Feature#13016] String#gsub(hash) Issue #13016 has been updated by Shyouhei Urabe. Martin D��rst wrote: > Shyouhei Urabe wrote: > > I noticed that I can't purge `NKF.nkf '-Z4'`. It can neither be rewritten using String#tr, String#encode, nor String#unicode_normalize. > > Can you give (a pointer to) a detailed description of what NKF, and in particular NKF.nkf -Z4, does exactly? For example, I can't find it at http://blog.layer8.sh/ja/2012/03/31/nkf_command_option/. It seems there are quite few resources describing this feature on line. - I learned it by command line "nkf --help". The output says "4: JISX0208 Katakana to JISX0201 Katakana". - A few minutes of googling let me realize that it has beed there at least since 2009. https://osdn.net/projects/nkf/news/17482 (Japanese). - It seems this is the particular commit which implemented the feature in nkf: https://github.com/nurse/nkf/commit/958de30bc09aef38f2a44b5da0dbb1bb3c79e7d3 - and then copied into our repository in this commit: https://github.com/ruby/ruby/commit/086e5b1a63d77bf5a4ebe10396a430d544fbe505 So in short it converts characters into what Unicode calls the "Halfwidth" ones. > Please note that String#unicode_normalize, as currently implemented, also uses some huge regular expressions (though program-generated). And also has (hopefully) successfully been debugged, although with the help of testing data from Unicode. Thank you. That still sounds like a hustle to me. The proposed functionality would make it a lot easier for me to emulate NKF's Z4. ---------------------------------------- Feature #13016: String#gsub(hash) https://bugs.ruby-lang.org/issues/13016#change-61931 * Author: Shyouhei Urabe * Status: Open * Priority: Normal * Assignee: ---------------------------------------- Background: I wanted to drop NKF dependency of my script. By doing so I noticed that I can't purge `NKF.nkf '-Z4'`. It can neither be rewritten using String#tr, String#encode, nor String#unicode_normalize. It is doable using String#gsub theoretically, but that requires a hand-crafted nontrivial regular expression that exactly matches what Z4 expects to convert. This is almost impossible to do, and is definitely not something debuggable. Proposal: extend String#gsub so that it also accepts hash as its only argument, specifying input-output mapping. ```ruby # now def convert str require 'nkf' NKF.nkf '-Z4xm0', str end # proposed def convert str map = { "\u3002" => "\uFF61", "\u300C" => "\uFF62", ... } str.gsub map end ``` -- https://bugs.ruby-lang.org/ Unsubscribe: