From: shyouhei@... Date: 2017-03-28T02:06:52+00:00 Subject: [ruby-core:80414] [Ruby trunk Bug#13371] Syntax Error with regex when parens are omitted Issue #13371 has been updated by shyouhei (Shyouhei Urabe). ndn (Nikola Nenkov) wrote: > Yes, but it was more of a question if it's a bug or not. Like should I use `%r//` when omitting parens as a principle? If yes - I would submit a PR in Rubocop and so on. I can't say for sure from memory but this language ambiguity between regular expressions versus binary division is very hard to reroute, if not impossible. So even if this is a bug, yes I recommend you to use %r. I think it wouldn't be fixed anytime soon. ---------------------------------------- Bug #13371: Syntax Error with regex when parens are omitted https://bugs.ruby-lang.org/issues/13371#change-63909 * Author: ndn (Nikola Nenkov) * Status: Open * Priority: Normal * Assignee: * Target version: * ruby -v: 2.4.1 * Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN ---------------------------------------- When you skip the parens of method invocations and pass a regex, you can get a `SyntaxError` if the regex starts with a space. ~~~ ruby ''.split(/ ./) # => [] ''.split /./ # => [] ''.split / ./ # !> SyntaxError: unexpected '.' ~~~ As per the syntax highlighting in my text editor and a discussion with another person, it seems that the opening slash is interpreted as division: ~~~ ruby require 'ripper' Ripper.lex("''.split /./") # => # [[[1, 0], :on_tstring_beg, "'"], # [[1, 1], :on_tstring_end, "'"], # [[1, 2], :on_period, "."], # [[1, 3], :on_ident, "split"], # [[1, 8], :on_sp, " "], # [[1, 9], :on_regexp_beg, "/"], # # ^^^ # [[1, 10], :on_tstring_content, "."], # [[1, 11], :on_regexp_end, "/"]] Ripper.lex("''.split / ./") # => # [[[1, 0], :on_tstring_beg, "'"], # [[1, 1], :on_tstring_end, "'"], # [[1, 2], :on_period, "."], # [[1, 3], :on_ident, "split"], # [[1, 8], :on_sp, " "], # [[1, 9], :on_op, "/"], # # ^^^ # [[1, 10], :on_sp, " "], # [[1, 11], :on_period, "."], # [[1, 12], :on_op, "/"]] ~~~ Reproducible with older versions as well (tried it until 2.1.2) -- https://bugs.ruby-lang.org/ Unsubscribe: