add examples

examples/splitjoin.lua

@@ -0,0 +1,86 @@
+local vim_repeat = require 'u.repeat'
+local CodeWriter = require 'u.codewriter'
+local Range = require 'u.range'
+
+local M = {}
+
+---@param bracket_range Range
+---@param left string
+---@param right string
+local function split(bracket_range, left, right)
+  local code = CodeWriter.from_pos(bracket_range.start)
+  code:write_raw(left)
+
+  local curr = bracket_range.start:next()
+  if curr == nil then return end
+  local last_start = curr
+
+  -- Sanity check: if we "skipped" past the start/stop of the overall range, then something is wrong:
+  -- This can happen with greater-/less- than signs that are mathematical, and not brackets:
+  while curr > bracket_range.start and curr < bracket_range.stop do
+    if vim.tbl_contains({ '{', '[', '(', '<' }, curr:char()) then
+      -- skip over bracketed groups:
+      local next = curr:find_match()
+      if next == nil then break end
+      curr = next
+    else
+      if vim.tbl_contains({ ',', ';' }, curr:char()) then
+        -- accumulate item:
+        local item = vim.trim(Range.new(last_start, curr):text())
+        if item ~= '' then code:indent():write(item) end
+
+        local next_last_start = curr:next()
+        if next_last_start == nil then break end
+        last_start = next_last_start
+      end
+
+      -- Prepare for next iteration:
+      local next = curr:next()
+      if next == nil then break end
+      curr = next
+    end
+  end
+
+  -- accumulate last, unfinished item:
+  local pos_before_right = bracket_range.stop:must_next(-1)
+  if last_start < pos_before_right then
+    local item = vim.trim(Range.new(last_start, pos_before_right):text())
+    if item ~= '' then code:indent():write(item) end
+  end
+
+  code:write(right)
+  bracket_range:replace(code.lines)
+end
+
+---@param bracket_range Range
+---@param left string
+---@param right string
+local function join(bracket_range, left, right)
+  local inner_range = Range.new(bracket_range.start:must_next(), bracket_range.stop:must_next(-1), bracket_range.mode)
+  local newline = vim
+    .iter(inner_range:lines())
+    :map(function(l) return vim.trim(l) end)
+    :filter(function(l) return l ~= '' end)
+    :join ' '
+  bracket_range:replace { left .. newline .. right }
+end
+
+local function splitjoin()
+  local bracket_range = Range.find_nearest_brackets()
+  if bracket_range == nil then return end
+  local lines = bracket_range:lines()
+  local left = lines[1]:sub(1, 1) -- left bracket
+  local right = lines[#lines]:sub(-1, -1) -- right bracket
+
+  if #lines == 1 then
+    split(bracket_range, left, right)
+  else
+    join(bracket_range, left, right)
+  end
+end
+
+function M.setup()
+  vim.keymap.set('n', 'gS', function() vim_repeat.run(splitjoin) end)
+end
+
+return M