Format unicode blocks to lua table

unicode_blocks.lua

--
-- Format table:
-- unicode.blocks = {
--  ['Domino-Tiles'] = "\u{1F030}-\u{1F09F}",
--  ['Supplemental-Arrows-C'] = "\u{1F800}-\\u{1F8FF}",
-- ...
-- }
--

-- Blocks.txt = https://www.unicode.org/Public/UNIDATA/Blocks.txt
local unicodeBlocks = {}

for line in io.lines('Blocks.txt', "*l") do
  local firstChar = line:sub(1, 1)
  if firstChar == '#' or firstChar == '' then
    goto continue
  end

  -- Capture
  local startCode, endCode, name = line:match('([A-Z0-9]+)%.%.([A-Z0-9]+); (.+)')
  if not (startCode and endCode and name) then
    goto continue
  end

  name = name:gsub(' ', '-')

  -- Add
  unicodeBlocks[name] = ('\\u{%s}-\\u{%s}'):format(startCode, endCode)

  ::continue::
end

local function getChars(property)
  local start = tonumber(property:match('^\\u{(.+)}%-'), 16)
  local finish = tonumber(property:match('^\\u{.+}%-\\u{(.+)}'), 16)

  local result = ''
  for codepoint = start, finish do
    result = result .. utf8.char(codepoint)
  end
  return result
end

return {
  blocks = unicodeBlocks,
  getChars = getChars,
}