vmp: the most ambitious vim emulator

I'm t9md

• My editor history: Vim > Emacs > Vim > Atom
• Emacs's limitless extensibility plant never give up sprit to me and it also made me editor addict.
• Vim plugins: choosewin, qickhl, smalls, textmanip, vim-chef, and more
• Atom packages: vim-mode-plus, narrow, quick-highlight, cursor-history, and more..(over 30 pkgs!).

Are you familiar with this endless editor tuning loop?.

• Frustration > Yes I can improve it > Ya I did it!! Oh, I found another frustration point > oh, I've spent too much hours!.

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What is the vim-mode-plus(VMP)?

• It's Atom editor package which provides vim keybinding and plus more.
• This is fork of vim-mode created by GitHub , they now deprecated it in favor of vmp.

Version	Date	Event
v0.0.0	2015-08-01	fork GitHub's vim-mode
v0.1.1	2015-09-28	1st public
v1.13.0	2017-10-27	185th release in 818 days (2 years + 3 months)

AVG. 1 release / 4.5 days !!

I'm still keeping high pace release cycle as first year of vmp.

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Who use vmp?

• Jordan Walke(ReactJS, ReasonML)
  • https://twitter.com/jordwalke/status/911889758208499712
• Cheng Lou(ReactMotions, ReasonML)
  • https://twitter.com/_chenglou/status/903159866172235776
• Richard Feldman(Elm book author, evangelist)
• Kent C Todd(Author of lots of npm modules and more).
  • https://twitter.com/kentcdodds/status/898888597465477123
• Michael Jackson(React Router, React Training)
  • https://twitter.com/mjackson/status/913551031656636416
• Ryan Florence(React Router, React Training)
  • https://twitter.com/ryanflorence/status/918346908225085440

Some says vmp is the best vim emulator.
IMO, maybe it's because of precise cursor placement.(e.g. cursor placement after undo or redo operation).

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What I will talk today

Part1. Understand editing in Vim

• What is editing in Vim
• How it's implemented and executed
• What is Motion, TextObject and Operator

Part2. vmp's unique features

• UX improvement
• Cursor placement
• One key TextObject
• Occurrence

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Part1. Understand editing in Vim

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What is editing in Vim?

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Why can your j keystroke move-down cursors

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Operation's life in stack on operationStack

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Motion, TextObject, Operator

Motion: j, k, {, g g...

• Move cursor from here to there.
• When used as TARGET, select here-to-there.

TextObject: i p, i w, a W...

• Select text range, always used as TARGET.
• Select same range as long as cursor is within that range
  • i w select same word as long as cursor is within that word.

Operator: d, c, y...

• Mutate TARGET
• Always require TARGET. "I will wait until I get target!".

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Summary

Editing is to transform text by mutation.

You build mutation instruction through keystroke.

Each keystroke invoke one of Operator, Motion or TextObject.

Formula: Mutation = Operator + Target(= Motion or TextObject)

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Part2. VMP's unique features

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DEMO session

demo file I used in talk

• Select operator
• TransformString operators
• Edge motion
• Occurrence
• Persistent selection
• Practical use of occurrence etc...

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Flash target

• vmp flashes an operator's target and also flashes changes on undo, redo.
• When you type y i p, it flashes i p range with CSS keyframe animation.
• With flash, you can be more confident for your operation.

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UI feedback on surround

• Surround is difficult for me.

• Because I have to type many keystrokes without mistake, without any UI feedback.

  • y s i w (: surround(y s) inner-word(i w) with (.

• vmp gives proper UI feedback to make surround easy to use, easy to understand

  • Select target immediately after target was provide(i w) and before you input final surround-char.
  • When change-surround, it shows char will be change at hover indicator.

• This GIF is after you type c s " and before you input final '

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Tunable f behavior and flash find-char.

• f is difficult. Where to stop next?.
• With flashing finding-char, you can predict where to stop next.
• I like all vim-seek, clever-f and vim-sneak, I want all of it's goodness.
  • Make it configurable to find across lines, number of chars to find, auto confirm by timeout, reuse f as ;...
  • You can tune vmp's f as you like.

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Eliminate unwanted cursor move

• What if cursor is not moved after y i p?
  • In pure-Vim, cursor is moved to start of paragraph.
• IMO, moving cursor after operator is unwanted side-effect.
• vmp introduces various stayOnXXX configuration and all have enabled by default.
  • In pure-Vim, stayOnVerticalMotion + stayOnDelete is doable by :set startofline=false

stayOnXXX configurations

• Keep cursor positions after operator y i p, d d, g U i p..
  • stayOnTransformString, stayOnYank, stayOnDelete, stayOnOccurrence
• Keep column when selecting TextObject v i p, v i i..
  • stayOnSelectTextObject
• keep column on vertical motion g g, G...
  • stayOnVerticalMotion

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One-key for VIP(Very ImPortant) TextObject

• You can type y p instead of y i p. How many times have you ever typed i p in your life!?
• Why? Some keys are freely available in operator-pending-mode.
• Since Operator is waiting for Target(Motion or TextObject) only. Remember Operator + Target rule?.
• So Operator + Operator keystroke(y d, d p...) makes no sense, OK to re-map.
  • One exception, same-operator-twice(d d, y y...) keystrokes have special meaning.

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Occurrence

• Noticed patterns in coding. I'm repeating same operation on same keyword again and again.
• With occurrence, you can bulk apply operator to all occurrences of keyword within target.
• You can edit more declaratively than imperatively, also can reduces need of . repeat.

Occurrence: How it works

Occurrence is not difficult, technically it's marker edit

• Mark keyword under cursor then edit as in normal way.
• You can mark keyword by either of following way
  • operator-modifier: o(word) and O(subword).(e.g. d o p, c O z)
  • preset-occurrence command: g o and g O. I'm remapping to m and M locally.

1. Mark keyword by g o or g O(subword)
2. Select visually
3. c to change, I to insert at start A to append to end of occurrence.

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Advice to improve vim-skill

• Understand this formula. Editing = Operator + Target(Motion or TextObject).

  • Install Operator + Target mental model into your brain by shouting loudly while typing.
  • y("Operator"!!) i p("Target!!")

• Pick and master from high-return Motion, TextObject first.

  • Motion: g g, G, [, ](VMP only)
  • TextObjet: i p, i w, i z(VMP only), i ,(VMP only)

• Use it in daily editing.

• Repeat, repeat, repeat! Till your finger moves without THINKING.

  • Vim: y i p, y i p, y i p... c i p, c i p... d i p...
  • Vim: y i ,, y i ,, y i ,... c i ,, c i ,... d i ,...
  • vmp shorthand: y p, y p, y p... c p, c p... d p...
  • vmp shorthand: y ,, y ,, y ,... c ,, c ,... d ,...

• Gradually increase TextObject, Motion of daily use.

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: VMP is the most ambitious vim emulator in the world(IMO!).

• Bundled so many non-default Motion, TextObject, Operator.
• Introduces new editing concept: e.g. occurrence, persistent-selection.
• UX improvement to make Vim easy to use, easy to understand.
• vmp is NOT aiming to become a perfect Vim emulator(no interest!).
• My mental stance is just borrowing favorite Vim features.
• Motivation is to experiment what-if ideas with hackable editor(Atom!).
• Ideas comes from frustration I encounter in daily vmp-dev. Endless feedback loop!
• I'm really SERIOUS for vmp, but vmp is NOT STRICT.

This GIF is now removed "show operator representing emoji" feature. You see how vmp is NOT strict?

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Thank you!!!