index.js
function parseCell(cell) {
  var match = cell.match(/([a-z]+)([0-9]+)/i)
  if(!match) throw new Error('invalid cell id '+cell)
  return [column.fromStr(match[1]), parseInt(match[2])]
}
function parseCell(cell) {
  var match = cell.match(/([a-z]+)([0-9]+)/i)
  if(!match) throw new Error('invalid cell id '+cell)
  return [column.fromStr(match[1]), parseInt(match[2])]
}
Utility functions