Module:Convert
Documentation for this module may be created at Module:Convert/doc
--[[
TODO Too many items to list, but following are some points:
- Output needs rather than space in several places.
- Some conversions require two outputs: {{convert|55|nmi|km mi}}.
- Some units have two values: {{convert|3.21|m|ftin}}.
- Remove commas from input numbers; add to output (always?).
- Use U+2212 MINUS SIGN for input + output number, not '-'.
]]--
--[[-----BEGIN DATA TABLE-----
Plan to write a program to generate the conversion tables below.
The input would be a text file in human-friendly format, and
the output would be the following tables.
When a lot of data is added, it might be useful to put this in another module.
Values from http://en.wikipedia.org/wiki/Conversion_of_units
Check with http://en.wikipedia.org/wiki/Template:Convert/list_of_units
]]--
local SIprefixes = {
['Y'] = { exponent = 24, name = 'yotta' },
['Z'] = { exponent = 21, name = 'zetta' },
['E'] = { exponent = 18, name = 'exa ' },
['P'] = { exponent = 15, name = 'peta ' },
['T'] = { exponent = 12, name = 'tera ' },
['G'] = { exponent = 9, name = 'giga ' },
['M'] = { exponent = 6, name = 'mega ' },
['k'] = { exponent = 3, name = 'kilo ' },
['H'] = { exponent = 2, name = 'hecto' }, -- not an SI prefix, but allow for people typing this
['h'] = { exponent = 2, name = 'hecto' },
['da']= { exponent = 1, name = 'deca ' },
['D'] = { exponent = 1, name = 'deca ' }, -- not an SI prefix, but allow for people typing this
['d'] = { exponent = -1, name = 'deci ' },
['c'] = { exponent = -2, name = 'centi' },
['m'] = { exponent = -3, name = 'milli' },
['µ'] = { exponent = -6, name = 'micro' },
['u'] = { exponent = -6, name = 'micro' }, -- not an SI prefix, but allow for people typing this
['n'] = { exponent = -9, name = 'nano ' },
['p'] = { exponent =-12, name = 'pico ' },
['f'] = { exponent =-15, name = 'femto' },
['a'] = { exponent =-18, name = 'atto ' },
['z'] = { exponent =-21, name = 'zepto' },
['y'] = { exponent =-24, name = 'yocto' },
}
local units = {
lookup = function (self, unit)
-- Return true, t where t is the unit's converter table (or false, message).
-- Given 'unit' is a symbol (like 'g'), with an optional SI prefix (as in 'kg').
-- If, for example, 'kg' is in this table, that entry is used; otherwise prefix is applied.
local t = self[unit]
if t ~= nil then
return true, { utype = t.utype, scale = t.scale, offset = t.offset, baseunit = unit, prefix = "" }
end
for plen = 2, 1, -1 do
-- Check for longer prefix first ('dam' is decametre).
local prefix = string.sub(unit, 1, plen)
local si = SIprefixes[prefix]
if si ~= nil then
local baseunit = unit:sub(plen+1)
local t = self[baseunit]
if t ~= nil and t.prefixes == true then
return true, { utype = t.utype, scale = t.scale * 10^si.exponent, offset = t.offset, baseunit = baseunit, prefix = prefix }
end
end
end
local msg = 'Unit %s is not known.[[Category:Convert unknown unit]]'
return false, msg:format(unit)
end,
-- The scales and offsets for mass convert to kilogramme as the intermediary unit.
['g'] = { utype = 'mass', scale = 0.001, offset = 0, prefixes = true},
['lb'] = { utype = 'mass', scale = 0.45359237, offset = 0, },
['oz'] = { utype = 'mass', scale = 0.45359237/16, offset = 0, },
['toz'] = { utype = 'mass', scale = 0.0311034768, offset = 0, },
-- The scales and offsets for length convert to metre as the intermediary unit.
['m'] = { utype = 'length', scale = 1, offset = 0, prefixes = true},
['mi'] = { utype = 'length', scale = 1609.344, offset = 0, },
['ft'] = { utype = 'length', scale = 0.3048, offset = 0, },
['yd'] = { utype = 'length', scale = 0.3048 * 3, offset = 0, },
['in'] = { utype = 'length', scale = 0.0254, offset = 0, },
-- The scales and offsets for temperature convert to Kelvin as the intermediary unit.
['K'] = { utype = 'temperature', scale = 1, offset = 0, },
['C'] = { utype = 'temperature', scale = 1, offset = -273.15, },
['F'] = { utype = 'temperature', scale = 5/9, offset = 32-273.15*(9/5),},
-- The scales and offsets for area convert to square metre as the intermediary unit.
['m2'] = { utype = 'area', scale = 1, offset = 0, },
['a'] = { utype = 'area', scale = 100, offset = 0, prefixes = true},
['sqft'] ={ utype = 'area', scale = 0.09290304, offset = 0, },
['sqyd'] ={ utype = 'area', scale = 0.83612736, offset = 0, },
['acre'] ={ utype = 'area', scale = 4046.8564224, offset = 0, },
-- The scales and offsets for volume convert to cubic metre as the intermediary unit.
['m3'] = { utype = 'volume', scale = 1, offset = 0, },
['L'] = { utype = 'volume', scale = 0.001, offset = 0, prefixes = true},
['cuyd'] ={ utype = 'volume', scale = 0.764554857984, offset = 0, },
['USgal']={ utype = 'volume', scale = 0.003785411784, offset = 0, },
['USfloz']={ utype = 'volume', scale = 0.003785411784/128, offset = 0, },
['USpint']={ utype = 'volume', scale = 0.003785411784/8, offset = 0, },
['gal']= { utype = 'volume', scale = 0.00454609, offset = 0, },
['floz']= { utype = 'volume', scale = 0.00454609/160, offset = 0, },
['pint']= { utype = 'volume', scale = 0.00454609/8, offset = 0, },
}
-- Aliases.
units['°K'] = units['K']
units['°C'] = units['C']
units['°F'] = units['F']
local defaultunits = {
lookup = function (self, unit_table)
-- Return true, s where s = name of unit's default output unit (or false, message).
local baseunit = unit_table.baseunit
local prefix = unit_table.prefix
local unit = prefix .. baseunit
local t = self[unit]
if t ~= nil then return true, t[1] end
t = self[baseunit]
if t ~= nil and t.prefixes == true then
local defaultunit = t[prefix] or t[1]
return true, defaultunit
end
local msg = 'Unit %s has no default target conversion.[[Category:Convert unknown unit]]'
return false, msg:format(unit)
end,
-- Non-metric units default to one metric equivalent.
['ft'] = { 'm' },
['yd'] = { 'm' },
['in'] = { 'cm' },
['lb'] = { 'kg' },
['oz'] = { 'g' },
['toz'] = { 'g' },
['mi'] = { 'km' },
['F'] = { 'C' },
['°F'] = { '°C' },
['sqft'] ={ 'm2' },
['sqyd'] ={ 'm2' },
['sqmi'] ={ 'km2' },
['USgal']={ 'L' },
['USfloz']={ 'cL' },
['USpint']={ 'dL' },
['gal']= { 'L' },
['floz']= { 'cL' },
['pint']= { 'dL' },
-- Metric units default to various non-metric units, according to SI prefix.
['g'] = { 'lb', prefixes = true},
['m'] = { 'ft', prefixes = true, m = 'in', c = 'in', d = 'in', da = 'yd', H = 'yd', k = 'mi', M = 'mi', G = 'mi' },
['K'] = { 'C' },
['C'] = { 'F' },
['°K'] = { '°C' },
['°C'] = { '°F' },
['m2'] = { 'sqyd' },
['a'] = { 'acre', prefixes = true},
['m3'] = { 'cuyd' },
['L'] = { 'pint', prefixes = true, m = 'floz', c = 'floz', d = 'floz', da = 'gal', H = 'gal'},
}
-------END DATA TABLE-----
-- Configuration options to keep magic values in one location.
local config = {}
local function get_config(frame)
-- Return table of configuration options.
-- Unclear if this is currently needed, but it may help if adapting
-- code for a different wiki.
local cfg = {}
-- Following settings are defaults that can be overridden by template.
cfg.numdot = '.' -- decimal mark before fractional digits
cfg.numsep = ',' -- thousands separator for numbers (',', '.', or nil)
for k,v in frame:argumentPairs() do
cfg[k] = v -- arguments from template's {{#invoke:}}
end
-- Following settings are mandatory (to limit abuse).
cfg.maxsigfig = 20 -- maximum number of significant figures
return cfg
end
local function withseparator(text)
-- Return string for a number with thousand separators inserted.
-- Parameter text is a string like "-12345" or "12345.6789".
-- Separator is inserted only in the integer part (not in fraction).
-- Four-digit integer parts have a separator (like "1,234").
local numsep = config.numsep
if #numsep == 0 then
return text
end
local function insert(text, first, last)
local result = ''
while last >= first do
if last >= first + 3 then
result = numsep .. text:sub(last-2, last) .. result
last = last - 3
else
return text:sub(first, last) .. result
end
end
return result
end
local first = 1
local sign = text:sub(first, 1)
if sign == '+' or sign == '-' then
-- To handle Unicode minus (multibyte), perhaps use following:
-- first = text:find('%d')
first = 2
else
sign = ''
end
local last = text:find(config.numdot, first, true)
if last == nil then
last = #text
else
last = last - 1
end
return sign .. insert(text, first, last) .. text:sub(last+1)
end
local function formatnumber(value, sigfig)
-- Return result of converting number 'value' to a string,
-- rounded to 'sigfig' significant figures.
local format = string.format
local rep = string.rep
local sign = ''
local numdot = config.numdot
local function zeropad(text, dot)
count = sigfig - #text
if count <= 0 then
return text
end
return text .. dot .. rep('0', count)
end
if sigfig <= 0 then
sigfig = 1
elseif sigfig > config.maxsigfig then
sigfig = config.maxsigfig
end
if value == 0 then
return zeropad('0', numdot)
end
if value < 0 then
sign = '-' -- need proper Unicode minus
value = -value
end
local digits
local exp, frac = math.modf(math.log10(value))
if frac == 0 then
-- Value 1 gives frac = 0, and 0.1 gives frac = -0 (negative zero).
-- Both results give true in 'if frac == 0'.
digits = zeropad('1', '')
exp = exp + 1 -- adjust so dot is before digits
else
local prec = sigfig
if value > 1 then
prec = prec - 1 -- will be one sig fig before dot
end
digits = format(format('%%.%df', prec), 10^frac)
if value < 1 then
-- Is MediaWiki run in a locale where following might be '0,'?
assert(digits:sub(1, 2) == '0.', 'Bug: rounded number not 0.xxx')
digits = digits:sub(3)
else
if prec == 0 then
assert(digits:find(numdot, 1, true) == nil, 'Bug: unexpected dot')
else
assert(digits:sub(2, 2) == numdot, 'Bug: rounded number not x.xxx')
digits = digits:sub(1, 1) .. digits:sub(3)
end
exp = exp + 1 -- adjust so dot is before digits
end
end
if exp >= #digits then
digits = digits .. rep('0', exp - #digits) -- result has no dot
elseif exp <= 0 then
digits = '0' .. numdot .. rep('0', -exp) .. digits
else
digits = digits:sub(1, exp) .. numdot .. digits:sub(exp+1)
end
return sign .. digits
end
local function require_number(value, missing, invalid)
-- Return true, n where n = number equivalent to given value (or false, message).
-- Thousand separators (valid or not) are first removed.
if value == nil then return false, missing end
if type(value) == 'number' then return true, value end
local numsep = config.numsep
if #numsep > 0 then value = string.gsub(value, numsep, '') end
local number = tonumber(value)
if number == nil then return false, invalid:format(value) end
return true, number
end
local function require_integer(value, missing, invalid)
-- Return true, n where n = integer equivalent to given value (or false, message).
local success, number = require_number(value, missing, invalid)
if not success then return success, number end
if number ~= math.floor(number) then return false, invalid:format(value) end
return true, number
end
local function get_parms(pframe)
-- Return true, t where t is a table with all arguments passed to the template
-- converted to named arguments. The numeric args are used to add named args:
-- in_text, in_text2 (strings given for value, value2)
-- value, in_unit, out_unit, value2, range, round_to
-- (except for range, which is nil or a table, the named args that are
-- added here could be provided by the user of the template).
local range_types = { -- text to separate input, output ranges
['and'] = {' and ', ' and '},
['by'] = {' by ', ' by '},
['to'] = {' to ', ' to '},
['-'] = {'–', '–'},
['to(-)'] = {' to ', '–'},
['x'] = {' by ', ' × '},
['+/-'] = {' ± ', ' ± '},
}
local success, t
local args = {} -- arguments passed to template
for k,v in pframe:argumentPairs() do
args[k] = v
end
args.in_text = args[1]
success, t = require_number(args.in_text, 'Need value', 'Value "%s" must be a number')
if not success then return success, t else args.value = t end
local in_unit = args[2]
local i = 3
local range = range_types[in_unit]
if range ~= nil then
args.in_text2 = args[3]
success, t = require_number(args.in_text2, 'Need second value', 'Second value "%s" must be a number')
if not success then return success, t else args.value2 = t end
in_unit = args[4]
i = 5
end
local out_unit = args[i]
local round_to = args[i+1]
if in_unit == nil then return false, 'Need input unit' end
args.in_unit = in_unit
args.out_unit = out_unit
args.range = range
args.round_to = args.round_to or round_to -- allow named parameter
return true, args
end
local function default_roundto(intext, factor)
-- Return a default value for round_to (an integer like 2, 0, -2).
-- prec = (precision implied in intext)
-- = (#digits after dot, or negative of #zeroes before dot)
-- If conversion is multiplication by a factor, and
-- if factor >= 0.02, compensate prec by adding N where:
-- N factor is in range
-- 1 .02 : .2 = .1/5 : .1*2
-- 0 .2 : 2 = 1/5 : 1*2
-- -1 2 : 20 = 10/5 : 10*2
-- -2 20 : 200 = 100/5 : 100*2 etc.
-- TODO Exception required for temperature.
prec = 0
dot = intext:find('.', 1, true)
if dot ~= nil then
prec = intext:sub(dot+1):len()
if prec == 0 then
intext = intext:sub(1, -2)
end
end
if prec == 0 then
prec = -intext:match('0*$'):len()
end
if factor ~= nil and factor >= 0.02 then
prec = prec - math.floor(math.log10(factor*5))
end
return prec
end
local function scaled(value, in_unit, out_unit)
-- Return scaled value for a simple convert.
return (value - in_unit.offset)
* (in_unit.scale / out_unit.scale)
+ out_unit.offset
end
local function cvtround(invalue, intext, parms)
-- Return true, s where s = rounded, formatted string from converting invalue,
-- using the rounding specified in parms (s = '' if invalue == nil).
-- This code combines convert/round because some rounding requires
-- knowledge of what we are converting.
-- TODO Lots of checking required. Will need tweaks for special cases
-- handled by old Template:Convert.
-- TODO Limit values to avoid abuse (for example, can currently set
-- round_to to very large values like 999).
local text = ''
if invalue == nil then return true, text end
local outvalue = scaled(invalue, parms.in_unit_table, parms.out_unit_table)
local round_to = parms.round_to
local sigfig = parms.sigfig
local disp = parms.disp
local auto = false
if round_to then
-- Ignore sigfig, disp.
success, round_to = require_integer(round_to, 'Need value', 'round_to "%s" must be an integer')
if not success then return success, round_to end
elseif sigfig then
-- Ignore disp.
success, sigfig = require_integer(sigfig, 'Need value', 'sigfig "%s" must be an integer')
if not success then return success, sigfig end
if sigfig <= 0 then
msg = 'sigfig "%s" must be positive'
return false, msg:format(parms.sigfig)
end
text = formatnumber(outvalue, sigfig)
elseif disp == '5' then
local negative = false
if outvalue < 0 then
negative = true
outvalue = -outvalue
end
outvalue = math.floor((outvalue / 5) + 0.5) * 5
if negative then
outvalue = -outvalue
end
text = string.format('%.0f', outvalue)
else
auto = true -- using default rounding
-- TODO If conversion is not multiplication by a number, need factor = nil.
local factor = outvalue / invalue
round_to = default_roundto(intext, factor)
end
if round_to then
if round_to >= 0 then
if auto then
-- TODO No less than two significant figures.
end
-- It seems format('%d', x) uses modf to extract integer from x
-- with result '0' if x is 0 or -0 (negative zero).
-- Using format('%.0f', x) gives '-0' if x is negative zero.
local fmt = '%.' .. string.format('%d', round_to) .. 'f'
text = string.format(fmt, outvalue)
else
-- This always keeps two sig figs. Should that be done if not auto?
round_to = -round_to -- #digits that want to zero
local maxzeroes = 0 -- maximum #digits that should be zeroed
if outvalue > 100 then
maxzeroes = math.modf(math.log10(outvalue)) - 1
end
if round_to > maxzeroes then
round_to = maxzeroes
end
if round_to > 0 then
local scaled = string.format('%.0f', outvalue/(10^round_to))
text = scaled .. string.rep('0', round_to)
else
text = formatnumber(outvalue, 2) -- can't zero digits; keep 2 sig figs
end
end
end
return true, withseparator(text)
end
local disp_single = {
['or'] = '%s %s or %s %s',
['sqbr'] = '%s %s [%s %s]',
['comma'] = '%s %s, %s %s',
['b'] = '%s %s (%s %s)',
}
local disp_double = {
['or'] = '%s%s%s %s or %s%s%s %s',
['sqbr'] = '%s%s%s %s [%s%s%s %s]',
['comma'] = '%s%s%s %s, %s%s%s %s',
['b'] = '%s%s%s %s (%s%s%s %s)',
}
local function process(parms)
-- Return true, s where s = final wikitext result (or false, message).
local success, t
success, t = units:lookup(parms.in_unit)
if not success then return success, t else parms.in_unit_table = t end
if parms.out_unit == nil then -- need to catch empty string also?
success, t = defaultunits:lookup(parms.in_unit_table)
if not success then return success, t else parms.out_unit = t end
end
success, t = units:lookup(parms.out_unit)
if not success then return success, t else parms.out_unit_table = t end
if parms.in_unit_table.utype ~= parms.out_unit_table.utype then
local msg = 'Cannot convert %s to %s.[[Category:Convert dimension mismatch]]'
return false, msg:format(parms.in_unit_table.utype, parms.out_unit_table.utype)
end
local intext1, outtext1 = parms.in_text, nil
local intext2, outtext2 = parms.in_text2, nil
success, outtext1 = cvtround(parms.value, intext1, parms)
if not success then return success, outtext1 end
success, outtext2 = cvtround(parms.value2, intext2, parms)
if not success then return success, outtext2 end
local range = parms.range
local disp = parms.disp
local wikitext
intext1 = withseparator(intext1) -- TODO what if intext1 already has commas?
if range == nil then
wikitext = disp_single[disp] or disp_single['b']
wikitext = wikitext:format(intext1, parms.in_unit, outtext1, parms.out_unit)
else
wikitext = disp_double[disp] or disp_double['b']
wikitext = wikitext:format(intext1, range[1], intext2, parms.in_unit, outtext1, range[2], outtext2, parms.out_unit)
end
return true, wikitext
end
-- Used by template {{convert2}}.
-- We will have to keep old {{convert}} for a long time, and run
-- {{convert2}} in parallel with {{convert}} while testing/developing.
local p = {}
local bodge = require "Module:mw" -- This fixes up mw.text.tag for us.
function p.convert(frame)
config = get_config(frame)
local pframe = frame:getParent()
local parms, text
success, parms = get_parms(pframe)
if success then
success, text = process(parms)
end
if not success then
local params = {style="color:black; background-color:orange;"}
text=mw.text.tag({name="span", contents="[[Module talk:Convert|Conversion error]]: " .. text, params=params})
end
return text
end
return p