Module:Rates

Documentation for this module may be created at Module:Rates/doc

local p = {}

local wholeFractions =
{
  [0.9] = "9/10",
  [0.88] = "22/25",
  [0.875] = "7/8",
  [0.85] = "17/20",
  [0.8] = "4/5",
  [0.6] = "3/5",
  [0.5625] = "9/16",
  [0.55] = "9/20",
  [0.5] = "1/2"
}

function p.calcRate(frame)
  return frame.args[1]*frame.args[2]
end

local function fmtRate(rate, fmt, digits)
  local out = ""
  if digits == nil then
    digits = 0
  end
  local frac = {}
  for number in string.gmatch(rate, '([^/]+)') do
    table.insert(frac, number)
      -- first time here is num, second time is den
      -- third and beyond invalid
  end
  if frac[2] == nil then
    frac[2] = 1
  end
  local num = frac[1]
  local den = frac[2]
  rate = num / den
  if fmt == "f" then
    if wholeFractions[rate] == nil then
      if rate < 10 then
        digits = math.max(digits, 2)
      elseif rate < 100 then
        digits = math.max(digits, 1)
      else
        digits = math.max(digits, 0)
      end
      out = out .. string.format("%s", string.format("1/%." .. digits .. "f", 1/rate)):gsub("%.?0+$", "")
    else
      out = out .. wholeFractions[rate]
    end
    return out
  elseif fmt == "p" then
    rate = string.format("%s%%", string.format("%f", string.format("%.5f", rate*100)):gsub("%.?0+$", ""))
    out = out .. rate
    return out
  end
end

function p.displayRate(frame)
  local rate = frame.args[1]
  local fmt = frame.args[2]
  local digits = frame.args[3]
  local out = ""
  if fmt == "f" then
  	out = out .. fmtRate(rate, "f", digits)
  elseif fmt == "p" then
    out = out .. fmtRate(rate, "p")
  elseif fmt == "n" then
    out = out .. fmtRate(rate, "f", 2) .. " (" .. fmtRate(rate, "p") .. ")"
  end
  return out
end

return p