Regexplainer

(h, j, k, l)

👋

• I Have Two Problems

• const [, pkg] =
    spec.match(/@patternfly\/pfe-([-\w]+)\/?(.*)/)

Atom Expat

• 🧰 Hackability 🔌 Plugins 🐿️ TreeSitter
• atom-regex-railroad

Do YOU know any hackable editors?

Doing NeoVim

• 🌘 Moon-Oriented Programming 🖥️
• 🐒 Climbing Trees 🌴

Code Spelunking

• Components

  ⚙️ What are we saying?

• Renderers

  ✍️ How are we saying it?

• Buffers

  🪟 Where are we saying it?

Components

local cursor_node = ts_utils.get_node_at_cursor()

local cursor_node = ts_utils.get_node_at_cursor()
local regexp_node = do_awful_hacks(cursor_node)

Everything we need

1. Combine sequential pattern_characters
2. Track capture groups and nesting levels
3. Translate control chars / quantifiers
4. Try to handle negative lookbehinds

{
  "regexp_string": "hello d([0-9]|o)lly",
  "components": [{
      "text": "hello d",
      "type": "pattern_character"
    }, {
      "capture_group": 1,
      "depth": 1,
      "text": "([0-9]|o)",
      "type": "anonymous_capturing_group",
      "children": [{
        "text": "[0-9]|o",
        "type": "alternation",
        "children": [{
          "text": "[0-9]",
          "type": "term",
          "children": [{
            "text": "0-9",
            "type": "class_range"
          }],
        }, {
          "text": "o",
          "type": "pattern_character"
        }],
      }],
    }, {
      "text": "lly",
      "type": "pattern_character"
  }]
}

Renderers

local M: Renderer = {}










return M

local M: Renderer = {}

function M.set_lines(buffer: Renderer,
                     lines: {string}): {string}
end






return M

local M: Renderer = {}

function M.set_lines(buffer: Renderer,
                     lines: {string}): {string}
end

function M.get_lines(components: {Component},
                     options: Options,
                     state: RendererState): {string}
end

return M

Buffers

Constructing a Narrative

function M.render(buffer: Buffer,
                  renderer: Renderer,
                  components: {Component},
                  options: Options,
                  state: RendererState)
  local lines = renderer
    .get_lines(components, options, state)
  buffer:init(lines, options, state)
  renderer.set_lines(buffer, lines)
  buffer:after(lines, options, state)
end

Demo Time!

Contributions Welcome

• 💻 Graphic output
• 👀 Negative Lookbehind
• 🔨 Refactoring
• 🥼 Tests

Thanks