Feature #15771
Updated by sawa (Tsuyoshi Sawada) over 4 years ago
When `String#split`'s separator is a single space character, it executes under `split_type: awk`. When you want to split literally by a single space `" "`, and not a sequence of space characters, you need to take special care. For example, the The CSV library detours this behavior like [this](https://github.com/ruby/csv/blob/7ff57a50e81c368029fa9b664700bec4a456b81b/lib/csv/parser.rb#L508-L512): ```ruby if @column_separator == " ".encode(@encoding) @split_column_separator = Regexp.new(@escaped_column_separator) else @split_column_separator = @column_separator end ``` Unfortunately, using a regexp here makes it slower than using a string. [The following result](https://github.com/284km/benchmarks_no_yatu#stringsplitstring-or-regexp) shows it is about nine times slower. ```sh $ be benchmark-driver string_split_string-regexp.yml --rbenv '2.6.2' Comparison: string: 3161117.6 i/s regexp: 344448.0 i/s - 9.18x slower ``` I want to add a `:literal` option to execute the method under `split_type: string`. ### Implementation - https://github.com/284km/ruby/tree/split_space - test code: https://github.com/284km/ruby/blob/split_space/test/ruby/test_string.rb#L1708-L1713 This change will result in the following: ```ruby " a b c ".split(" ") # => ["a", "b", "c"] " a b c ".split(" ", -1) # => ["a", "b", "c", ""] " a b c ".split(" ", literal: true) # => ["", "a", "", "b", "", "", "c"] " a b c ".split(" ", -1, literal: true) # => ["", "a", "", "b", "", "", "c", "", "", "", ""] ```