My daily life on Ruby

Slides for my RubyCon 2026 talk "My daily life on Ruby" https://rubycon.it/schedule/

1. My daily life on Ruby Akira Matsuda at 1 / 213
2. self 🍕 Akira Matsuda 🍕 A Rubyist from 🇯🇵 🍕 amatsuda on GH 2 / 213
3. self 🍕 Ruby committer 🍕 Rails committer 🍕 Gem author 🍕 Kaminari, active_decorator, action_args, jb, stateful_enum, database_rewinder, gem_src, traceroute, routes_lazy_routes, lightweight_attributes, everywhere, hocus_pocus, erd, i18n_generators, html5_validators, motorhead, heavens_door, still_life, roundabout... 🍕 Gem maintainer 🍕 Haml, SimpleCov, test-unit-rails, md2key, cfp-app... 3 / 213
4. self 🍕 Chief Organizer of RubyKaigi (since 2015) 🍕 Founder of Asakusa.rb (since 2008) 🍕 Ruby Hero (2016) 🍕 Rails Luminary (2024) 🍕 Loves 🇮🇹 Rock in '70s 🍕 Premiata Forneria Marconi, New Trolls, Area, Banco del Mutuo Soccorso, Arti e Mestieri, Semiramis, Biglietto per l'Inferno, Il Balletto di Bronzo, Museo Rosenbach, Formula 3, Jacula... 4 / 213
5. RubyKaigi 🍕 The world's largest international Ruby conference 5 / 213
6. 3 days Ruby festival 6 / 213
7. RubyKaigi 2026 🍕 2.weeks.ago 7 / 213
8. Attendees from 🌍 8 / 213
9. RubyKaigi 2026 ✋ 9 / 213
10. Today's topic 10 / 213
11. Development environment 11 / 213
12. Ruby dev environment in 2026 🍕 Terminal emulator 🍕 Shell 🍕 Text Editor 12 / 213
13. Layered into each software stack 🍕 We can choose one from each layer and combine them 13 / 213
14. Terminal emulators 🍕 iTerm2 🍕 alacritty 🍕 WezTerm 🍕 kitty 🍕 Ghostty 14 / 213
15. WezTerm 🍕 I used to use WezTerm 15 / 213
16. Ghostty 🍕 Switched to Ghostty last year 16 / 213
17. kitty 🍕 But let me talk about kitty a little bit 17 / 213
18. kitty? 18 / 213
19. kitty 🍕 Got a new feature recently 19 / 213
20. kitty 🍕 "The text sizing protocol" 20 / 213
21. The kitty text sizing protocol 🍕 https://github.com/kovidgoyal/kitty/issues/8226 🍕 Proposed and implemented last year 🍕 We can enlarge text size via OSC Escape Code (OSC 66) 21 / 213
22. Large Text! 22 / 213
23. Large Text! Larger Text! 23 / 213
24. Large Text! Even Larger Text! 24 / 213
25. So what can we do with this? 25 / 213
26. We can render Markdown in teminals! 26 / 213
27. Like this % mkd README.md 27 / 213
28. mkd 🍕 github.com/amatsuda/mkd 🍕 A Markdown viewer written in pure Ruby 🍕 By me 🍕 Renders Markdown nicely on terminals that support OSC 66 28 / 213
29. OSC 66 support in other terminal emulators? 🍕 Not yet 29 / 213
30. So we have to use kitty 🍕 If we want to try this feature 30 / 213
31. kitty 🍕 But, it's Python based... 31 / 213
32. Anyway, 32 / 213
33. What else would we do with this feature? 33 / 213
34. Perhaps, 🍕 We can create a presentation tool on terminal? 34 / 213
35. Like this 🍕 I mean, 35 / 213
36. Like this one that you're just watching 36 / 213
37. Yes, it's built with Ruby 🍕 And by me 37 / 213
38. przn 🍕 https://github.com/amatsuda/przn 🍕 Written as "przn", and pronounced as "przn" 38 / 213
39. Structure 🍕 parser.rb: Parses Markdown and builds the deck 🍕 controller.rb: Accepts key inputs and executes the commands 🍕 terminal.rb: Renders on the terminal using io-console 39 / 213
40. The Markdown syntax 🍕 Basically Rabbit compatible 40 / 213
41. io-console 🍕 A Ruby stdlib 🍕 Maybe not that popular? 🍕 A very few usages found on the web 🍕 A very handy tool to draw characters on console 🍕 Made by nobu, the patch monster 41 / 213
42. @nobu (Nobuyoshi Nakada) 🍕 No.1 Ruby committer (in terms of numbers of commits) 🍕 aka "Patch Monster" (or "Pachimon") 🍕 Maintains everything in Ruby 42 / 213
43. io-console 🍕 A Ruby stdlib 🍕 Maybe not that popular? 🍕 A very few usages found on the web 🍕 A very handy tool to draw characters on console 🍕 Made by nobu, the patch monster 43 / 213
44. Who have ever played with io-console before? ✋ 44 / 213
45. Let's play with io-console! 45 / 213
46. Demo % ruby demo/ioconsole.rb 46 / 213
47. Ruby libraries to deal with CLI/TUI 🍕 Readline 🍕 Curses 🍕 io-console 47 / 213
48. Readline 🍕 Ruby binding for GNU Readline 48 / 213
49. What does GNU Readline do? 🍕 It bridges between users' key inputs and the terminal/shell 49 / 213
50. Readline 🍕 Super legacy 🍕 Often fails to install for some reasons 🍕 Lacks some features that Ruby needs for irb 50 / 213
51. Readline 🍕 Used as irb's backend 51 / 213
52. irb 🍕 Rubyists' favorite Ruby REPL 🍕 Made by keiju 52 / 213
53. @keiju (Keiju Ishitsuka) 🍕 The godfather of Ruby 🍕 It was keiju who gave the name "Ruby" to Matz's language (1993) 🍕 Was Matz's colleague at that time 🍕 The author of irb 🍕 The author or Reish 53 / 213
54. Reish? 🍕 keiju planned to reinvent irb as a shell 54 / 213
55. Reish 🍕 https://github.com/keiju/reish 🍕 Pure Ruby UNIX shell 🍕 With Ruby-like shell syntax 55 / 213
56. Reish 🍕 And so he started from reinventing Readline in pure Ruby 🍕 Which was named Reidline 56 / 213
57. Reidline 🍕 But it never finished... 57 / 213
58. But this project inspired another project 58 / 213
59. Reline 🍕 Pure Ruby Readline implementation 🍕 Created by itoyanagi 🍕 Inspired by keiju's unfinished work "Reidine" 59 / 213
60. Reline 🍕 Totally replaced Readline (2019) 🍕 irb's backend today 🍕 Maintained by the irb team today 🍕 tompng, ima1zumi, st0012, and hasumikin 60 / 213
61. Ruby libraries to deal with CLI/TUI 🍕 Readline 🍕 io-console 🍕 Curses 🍕 Reline 61 / 213
62. @itoyanagi (Itoyanagi) 🍕 An adventurer 🍕 A legacy killer in Ruby 🍕 Killed RDoc's own parser in favor of Ripper 🍕 Created Reline 🍕 Achieved a big refactoring on irb on top of Reline 62 / 213
63. Demo % irb 63 / 213
64. Pure Ruby Readline equivalent has done 🍕 So it's time to create a pure Ruby shell on top of it? 🍕 As keiju planned? 64 / 213
65. I thought so, 65 / 213
66. And so I did 66 / 213
67. UNIX shell 67 / 213
68. Major modern shells 🍕 bash 🍕 zsh 🍕 fish 68 / 213
69. bash 🍕 The standard 69 / 213
70. zsh 🍕 The ultimate modern shell 🍕 bash compatible 🍕 Highly customizable 🍕 Advanced completion system 🍕 Brought the "plugin system" to the shell world 70 / 213
71. What does a shell do? 🍕 Provides interactive environment 🍕 Runs scripting language 71 / 213
72. sh's design as a scripting language 🍕 Pipeline-based 72 / 213
73. Limitations 🍕 Because it's pipeline-based 🍕 All inputs and outputs are strings 🍕 test commands does all the hard works under the hood 73 / 213
74. test command basics % test 1 = 1 % echo $? 0 % test 1 = 2 % echo $? 1 74 / 213
75. A tricky alias for test, [ % if [ "$FOO" = "hello" ]; then > echo true > fi 75 / 213
76. Trickiest part in sh languages 🍕 Does all the heavy liftings when comparing things 🍕 I won't go into details, but it has too many features and too many options 🍕 This makes even a simple if or loop statements hard to write 76 / 213
77. Too many options 🍕 -b, -c, -d, -e, -f, -g, -h, -k, -n, -p, -r, -s, -t, 🍕 -u, -w, -x, -z, -L, -O, -G, -S, 🍕 file1 -nt file2, file1 -ot file2, file1 -ef file2, 🍕 string, s1 = s2, s1 != s2, s1 < s2, s1 > s2, 🍕 n1 -eq n2, n1 -ne n2, n1 -gt n2, n1 -ge n2, n1 -lt n2, n1 -le n2 77 / 213
78. Then there came fish 78 / 213
79. fish 🍕 More modernized shell than zsh 🍕 Very much opinionated 🍕 Strong functions 🍕 Aggressive completion 🍕 Just works without lots of configurations 🍕 Unlike zsh 79 / 213
80. fish as a scripting language 🍕 bash incompatible 80 / 213
81. fish's biggest mistake 🍕 The scripting language is not bash-compatible! 81 / 213
82. The fish language 🍕 Trying to improve bash usability 🍕 I can understand the motivation 🍕 But the language design is... still not intuitive 🍕 I mean it doesn't feel like "my language" 82 / 213
83. fish 🍕 So it failed to dominate the market 🍕 Many people are still living with zsh 83 / 213
84. After all, we still don't have our endgame shell 84 / 213
85. So, as I said, I created my own 85 / 213
86. The feature that we need for our endgame shell 🍕 Ruby as the scripting language! 86 / 213
87. Reish again 87 / 213
88. Reish again 🍕 Even the creator of irb couldn't finish it 🍕 Why did I thought that I can do it? 88 / 213
89. AI 🍕 Because we have AI today 89 / 213
90. History 🍕 I started working on it from 1st, January this year 🍕 Roughly done in about two weeks 🍕 It's been my main login shell since then 90 / 213
91. Features 🍕 Written in pure Ruby 🍕 bash compatible 🍕 All existing bash scripts should just work 🍕 Ruby-flavored extended syntax 🍕 Covers most of zsh features 🍕 Just works without lots of configurations 91 / 213
92. Demo (completion) % cd % cd ~ % git % gem % bundle % rbenv 92 / 213
93. Ruby flavored language 🍕 if, elif, fi => if, elsif, end 🍕 Blocks 🍕 Method chaining 🍕 lambda literal 🍕 p command for inspecting in Ruby level 🍕 Ruby constant reference 🍕 Use of Ruby Threads for background processing 🍕 And many more experimental features 93 / 213
94. Blocks 🍕 if/loop commands take { } block that is evaled in Ruby 🍕 We can forget the test command 🍕 Enumerator 🍕 each, select, map 🍕 it is available 94 / 213
95. Demo if { 1 + 1 == 2 } echo "1 + 1 is 2" end 95 / 213
96. OMG! 🍕 This if statement is readable, writable, maintainable! 🍕 if ends with end ! 96 / 213
97. Method chaining 🍕 Commands take () like methods 🍕 So pipelines can be written as method chaining 97 / 213
98. Demo % ls(/usr/bin).select { it.start_with? 'a' } 98 / 213
99. Method? 99 / 213
100. Demo def ciao 'ciao' * 2 end 100 / 213
101. Ruby constant reference 🍕 There's no command or feature that starts with a Capital letter in UNIX 🍕 So, we can assume that if it starts with A-Z, it must be a Ruby constant 101 / 213
102. Demo % Time.now 102 / 213
103. Demo % Date.today 103 / 213
104. require 🍕 There's a built-in require command 104 / 213
105. Demo % require date 105 / 213
106. did_you_mean integration 106 / 213
107. Demo typo 107 / 213
108. Demo % -> { RUBY_VERSION } 108 / 213
109. Implementation 🍕 Reline based, like irb, as I told you 🍕 And heavily relies on the Ruby stdlibs 109 / 213
110. Standing on the shoulders of giant Ruby ecosystem 🍕 Reline 🍕 FileUtils 🍕 Open3 🍕 Thread 🍕 did_you_mean etc. 110 / 213
111. Repo 🍕 https://github.com/amatsuda/rubish 111 / 213
112. There are some problems though 112 / 213
113. Naming software is hard... 🍕 The gem name "rubish" was already taken... 🍕 Installable via homebrew for now... 113 / 213
114. The "system ruby" problem 🍕 A shell has to be loaded before loading rbenv or such 🍕 So the shell runs on "system Ruby" 🍕 Which is still 2.6 on Mac 🍕 Which is very old 114 / 213
115. The "system ruby" problem => Resolved! 🍕 Fixed by changing the executable to a bash script that detects other rubies 🍕 (This slide was added after the talk) 115 / 213
116. Anyway it works! 116 / 213
117. And so I started making another thing with Ruby 🍕 On top of Reline again 117 / 213
118. A text editor 118 / 213
119. I knew that a pure Ruby text editor is feasible 119 / 213
120. Because there already is a preceding case 120 / 213
121. Textbringer 121 / 213
122. Textbringer 🍕 shugo's editor in pure Ruby 🍕 Built on top of Curses 🍕 Emacs clone 122 / 213
123. @shugo (Shugo Maeda) 🍕 Creator of lots of weird (and lots of useful) features of Ruby 🍕 Creator of protected scope 🍕 Creator of callcc 🍕 Creator of Refinements 🍕 Creator of eruby (ERB specification) 🍕 Creator of mod_ruby (Apache module) 🍕 Creator of net-ftp/net-imap 🍕 Maintainer of Curses 🍕 Matz's boss at his company, NaCl 123 / 213
124. Curses 🍕 Ruby binding for curses, Ncurses, and PDCurses 🍕 For building richer TUI tools 🍕 Like tetris 🍕 Or text editor 🍕 shugo maintains this so his text editor keeps working 124 / 213
125. I once made a filer with Ruby Curses 🍕 And it beautifully works! 125 / 213
126. rfd 🍕 https://github.com/amatsuda/rfd 🍕 "FD" (a legendary Japanes filer for MS-DOS) clone 🍕 Vim-ish UI 🍕 Pure Ruby 🍕 On top of Curses 126 / 213
127. Anyway, 127 / 213
128. There's already one 🍕 There already is a working pure Ruby text editor 128 / 213
129. So why did I create my own? 129 / 213
130. Because Textbringer is an Emacs 130 / 213
131. The question (for me) 🍕 To Vim or not to Vim 131 / 213
132. rvim 🍕 https://github.com/amatsuda/rvim 🍕 Pure Ruby 🍕 Reline based (not Curses) 🍕 NeoVim clone (not Emacs) 132 / 213
133. Features 🍕 Covers most of basic features of NeoVim 🍕 Some critical features like async, LSP, and tree sitter are not supported yet 🍕 Covers most of settings (:set) 🍕 Kind of emulates VimScript 🍕 Executes Lua scripts! 133 / 213
134. Running Lua scripts from Ruby 🍕 I'm just using rufus-lua gem 🍕 And it magically works! 134 / 213
135. rufus-lua 🍕 A Ruby binding that calls Lua engine via FFI 🍕 Created by jmettraux 135 / 213
136. @jmettraux (John Mettraux) 🍕 A gentleman from Switzerland 🍕 Lives in Hiroshima, Japan 🍕 Author of rufus-scheduler and the family 136 / 213
137. So, it just works 137 / 213
138. That's everything that I wrote in my proposal 🍕 A pure Ruby UNIX shell 🍕 A pure Ruby text editor 138 / 213
139. I feel like I'm done! 🍕 So let me wrap up 139 / 213
140. Wrap up 🍕 I made pure Ruby shell and text editor 140 / 213
141. self 🍕 Akira Matsuda 🍕 A Rubyist from 🇯🇵 🍕 amatsuda on GH 141 / 213
142. end Grazie! 142 / 213
143. end...? Grazie...? 143 / 213
144. Future works 144 / 213
145. Missing features 🍕 Terminal integration 🍕 Like moving cursor and copy & paste with keyboard shortcuts 🍕 Like GNU Screen 145 / 213
146. That's something beyond shell's domain 🍕 That's terminal emulators' territory 🍕 For instance, kitty implements them on its own 146 / 213
147. kitty 🍕 kitty again 147 / 213
148. kitty 🍕 But, it's Python based... 148 / 213
149. Wait, 149 / 213
150. Python? 🍕 If there's a Python based terminal emulator 🍕 There should be no reason we cannot do it in Ruby!💡 150 / 213
151. And so I made it (and so this talk seems to continue a little bit more) 151 / 213
152. Echoes 🍕 https://github.com/amatsuda/echoes 🍕 Pure Ruby terminal emulator 🍕 Native UI components 🍕 Not based on Reline here 🍕 Supports only macOS so far 🍕 So the UI is COCOA based 152 / 213
153. Features 🍕 Any shell should work on it 🍕 Supports kitty text sizing protocol 🍕 So the presentation tool works on it 🍕 Supports image rendering 🍕 Even tetris works on it 🍕 Native UI based features 🍕 Native dialog! 🍕 Multiple fonts! 🍕 Multiple bg colors! 🍕 With gradations! 153 / 213
154. You're already seeing it today 🍕 Since the beginning of this talk 154 / 213
155. A pure Ruby terminal emulator 🍕 TBH, it'd be hard to beat alacritty, Ghostty and such in rendering speed 155 / 213
156. Then why am I creating it? 156 / 213
157. I have a vision 🍕 Integrating all these Ruby-made products 157 / 213
158. The CLI dev stack on which everyone lives today 🍕 Terminal Emulator 🍕 Shell 🍕 Text Editor 158 / 213
159. Connected with super legacy APIs 🍕 When the consoles displayed only 8 colors 🍕 When UNICODE was not a thing 🍕 When Ruby was not there yet 159 / 213
160. NORMAL TERMINAL ⁶ SHELL pty (one byte stream, bidirectional) ┌───────────┐ ◄─────────────────────►┌────────────┐ │ Terminal │ │ Shell │ │ │ keystroke bytes ──►│ │ │ - ANSI │ ◄─ echoed keystroke │- Reline │ │ parser │ + cursor ANSI │ parses │ │ - cell │ (round-trips) │ keys │ │ grid │ ◄─ prompt as │- prompt is │ │ │ ANSI bytes: │ formatted │ │ │ "\e[1;32m$\e[0m " │ as ANSI │ │ │ ◄─ completion list as │- completion│ │ │ text + ANSI │ pre-baked │ │ │ ◄─ command stdout │ to bytes │ └───────────┘ (also bytes) └────────────┘ 160 / 213
161. NORMAL TERMINAL ⁶ SHELL Two parsers (one in each side). Every keystroke makes a round trip. Prompt / completion / cursor moves are all flattened to escape codes — the terminal can't distinguish "this byte is part of the prompt" from "this byte is part of command output". Just one big stream. 161 / 213
162. Every API is designed as ASCII byte stream 162 / 213
163. So we have to perform a lot of String conversion dances 🍕 Here and there between the layers 🍕 Causes performance overhead 🍕 Causes mojibake 🍕 Causes exceptions, e.g. "invalid byte sequence in UTF-8" 163 / 213
164. Integration 🍕 What if we run everything in one Ruby process? 🍕 We could skip all the abstractions and legacy APIs in favor of simple Ruby method calls! 164 / 213
165. You know, that's called "full stack" 🍕 "full stack" is stronger than micro components 🍕 Ruby is good for building full stack software 🍕 The web framework proved it already 165 / 213
166. So, here it is! 166 / 213
167. Echoes integration 🍕 Echoes directly renders shell outputs via native API 🍕 Skipping legacy UNIX API 🍕 Skipping Reline as well! 167 / 213
168. Demo Showing a shell completion dialog in native UI 168 / 213
169. The text editor can be run there 🍕 Directly from with in the terminal emulator via one method call 🍕 Skipping the whole shell process 169 / 213
170. Demo Text editing (native version) 170 / 213
171. Let's call this 171 / 213
172. Echoes Act II 172 / 213
173. So am I reinventing an IDE? 🍕 Like Rubymine or VSCode 🍕 Well, maybe... 173 / 213
174. But for me it's way more exciting Or I'd say "Romantic" 174 / 213
175. To build everything myself with my favorite language 🍕 Instead of just downloading and using an IDE that is built for general purpose 175 / 213
176. Wrap up 176 / 213
177. Ruby dev environment in 2026 🍕 Terminal Emulator 🍕 Shell 🍕 Text Editor 177 / 213
178. I'm creating everything 178 / 213
179. I made pure Ruby dev tools for you! 🍕 Please try them, and give me feedbacks! 179 / 213
180. I made pure Ruby dev tools for you! 🍕 Please try them, and give me feedbacks! 180 / 213
181. No, this isn't what I really wanted to tell you today 181 / 213
182. I'm building my own dev tools 🍕 With Ruby 182 / 213
183. And I'm having fun with it! 183 / 213
184. I'm not a terminal pro 🍕 But AI made me possible to do this 184 / 213
185. And so can you, of course 🍕 We live in such an exciting world as a programmer! 185 / 213
186. I'm basically a Rails guy 186 / 213
187. As a Ruby on Rails committer 🍕 I'm happy if you use Rails 187 / 213
188. But I'm here today to tell you that 188 / 213
189. Ruby can do anything 🍕 Ruby is not just a language that runs Rails on the servers 🍕 Ruby has a very rich ecosystem 🍕 And Ruby is your best friend! 189 / 213
190. So, everybody, now that it's time 190 / 213
191. To cross Rubicon 191 / 213
192. To build a huge Ruby empire 192 / 213
193. The land where every software that we use is written in Ruby 🍕 So that it's readable 🍕 So that it's maintainable 🍕 So that it's extendable 193 / 213
194. And everyone feels happy about that 194 / 213
195. I would call it "Pax Rubyna" 195 / 213
196. RubyKaigi 2026 196 / 213
197. Topics 🍕 No Rails talk 🍕 Hacks for Ruby 🍕 Hacks with Ruby 197 / 213
198. If you're interested 198 / 213
199. RubyKaigi 2027 🍕 🗓 April 14..16 199 / 213
200. You'll see how people are enjoying Ruby 200 / 213
201. Playing with Ruby is fun 201 / 213
202. Let's play with Ruby! 202 / 213
203. Let's try using Ruby 🍕 For something that you've never tried 🍕 For tools that you actually use 🍕 For something that makes your life better 🍕 Or just for something fun 203 / 213
204. Let's make it with Ruby! 🍕 And :ship: 🇮🇹! 204 / 213
205. self 🍕 Akira Matsuda 🍕 A Rubyist from 🇯🇵 🍕 amatsuda on GH 205 / 213
206. Author of 🍕 Echoes 🍕 rubish 🍕 rvim 🍕 przn 🍕 mkd 206 / 213
207. end Grazie! 207 / 213
208. Q&A 208 / 213
209. Q: Why not Rust? Everyone creates such CLI tools with Rust (or zig or whatever) these days. Why don't you do so? 209 / 213
210. A: Why not Ruby? Who decided that Ruby is not the language for that? 210 / 213
211. Q: No tetris demo for Curses and Reline? 211 / 213
212. A: Why not? 212 / 213
213. end Grazie! 213 / 213