Module:Grammar/Conjugate

---

local p = {}

function p.pluralize(str, apostrophe)
  apostrophe = apostrophe or ''
  local irregularplurals = {
    man = 'men'
  }
  if irregularplurals[str] ~= nil then
    return irregularplurals[str]
  elseif (str:sub(-1) == 's') then
    return (str .. apostrophe)   --return unmodified (ends with 's', like 'boots', so we shouldn't append another 's')
  elseif (string.sub(str, -1) == 'y') and apostrophe == '' then
    return (string.sub(str, 1, -2) ..  'ies')
  elseif (str:sub(-1) == 'z' or str:sub(-2) == 'ch' or str:sub(-2) == 'sh' or str:sub(-1) == 'x') and apostrophe == '' then
    return (str ..  'es')
  else
    return (str.. apostrophe .. 's')
  end
end

function p.make_possessive(string)
  return p.pluralize(string, "'")
end

function p.singularverb(string)
  --[ Assumes the input string is already a plural verb.]
  local irregularsingulars = {
     ["are"] = 'is',
     ["were"] = 'was',
     ["have"] = 'has',
     ["'re"] = "'s",
     ["don't"] = "doesn't",
     ["'ve"] = "'s"
  }
  local result = irregularsingulars[string]
  if result ~= nil and result ~= '' then
    return result
  else
    return string .. "s"
  end
end

return p