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'] = 24,
['Z'] = 21,
['E'] = 18,
['P'] = 15,
['T'] = 12,
['G'] = 9,
['M'] = 6,
['k'] = 3,
['H'] = 2,
['h'] = 2, -- Not an SI prefix, but allow for people typing this (hectare as "ha", for example).
['da'] = 1,
['D'] = 1, -- Not an SI prefix, but allow for people typing this.
['d'] = -1,
['c'] = -2,
['m'] = -3,
['µ'] = -6,
['u'] = -6, -- Not an SI prefix, but allow for people typing this.
['n'] = -9,
['p'] = -12,
['f'] = -15,
['a'] = -18,
['z'] = -21,
['y'] = -24
}
local units = {
lookup = function (self, unit)
-- If unit is known, return its converter table.
local t = self[unit]
if t ~= nil then return t end
-- This could be done in a much more exciting, Luaist, way with a metatable.
for prefix,exponent in pairs(SIprefixes) do
local plen = prefix:len()
if #unit > plen and prefix == unit:sub(1,0+plen) then
local baseunit = unit:sub(plen+1,-1)
local baset = self[baseunit]
if baset ~= nil and baset.prefixes == true then
t = mw.clone(baset)
t[2] = t[2] * 10 ^ exponent
t.prefix = prefix
return t
end
end
end
local msg = 'Unit %s not known[[Category:Convert unknown unit]]'
error(msg:format(unit))
end,
-- The scales and offsets for mass convert to kilogramme as the intermediary unit.
['g'] = { utype = 'mass', scale = 1000, offset = 0, defaultunit = 'lb', prefixes = true},
['lb'] = { utype = 'mass', scale = 0.45359237, offset = 0, defaultunit = 'kg'},
['oz'] = { utype = 'mass', scale = 0.45359237/16, offset = 0, defaultunit = 'g'},
['toz'] = { utype = 'mass', scale = 0.0311034768, offset = 0, defaultunit = 'g'},
-- The scales and offsets for length convert to metre as the intermediary unit.
['m'] = { utype = 'length', scale = 1, offset = 0, defaultunit = 'ft', prefixes = true},
['mi'] = { utype = 'length', scale = 1609.344, offset = 0, defaultunit = 'km'},
['ft'] = { utype = 'length', scale = 0.3048, offset = 0, defaultunit = 'm'},
['yd'] = { utype = 'length', scale = 0.3048 * 3, offset = 0, defaultunit = 'm'},
['in'] = { utype = 'length', scale = 0.0254, offset = 0, defaultunit = 'cm'},
-- The scales and offsets for length convert to Kelvin as the intermediary unit.
['K'] = { utype = 'temperature', scale = 1, offset = 0, defaultunit = 'C'},
['C'] = { utype = 'temperature', scale = 1, offset = 273.15, defaultunit = 'F'},
['F'] = { utype = 'temperature', scale = 5/9, offset = 32 - 273.15, defaultunit = 'C'},
['°K'] = { utype = 'temperature', scale = 1, offset = 0, defaultunit = '°C'},
['°C'] = { utype = 'temperature', scale = 1, offset = 273.15, defaultunit = '°F'},
['°F'] = { utype = 'temperature', scale = 5/9, offset = 32 - 273.15, defaultunit = '°C'},
-- The scales and offsets for area convert to square metre as the intermediary unit.
['m2'] = { utype = 'area', scale = 1, offset = 0, defaultunit = 'sqyd'},
['a'] = { utype = 'area', scale = 0.01, offset = 0, defaultunit = 'acre'},
['sqyd'] ={ utype = 'area', scale = 0.83612736, offset = 0, defaultunit = 'm2'},
}
-------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).
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)
-- If value is missing or not a number, throw an error.
-- Thousand separators (valid or not) are first removed.
-- Return value as a number if valid.
if value == nil then error(missing) end
if type(value) == 'number' then return value end
local numsep = config.numsep
if #numsep > 0 then value = string.gsub(value, numsep, '') end
local number = tonumber(value)
if number == nil then error(invalid:format(value)) end
return number
end
local function require_integer(value, missing, invalid)
-- If value is missing or not an integer, throw an error.
-- Return value as a number if valid.
local number = require_number(value, missing, invalid)
if number ~= math.floor(number) then error(invalid:format(value)) end
return number
end
local function get_parms(pframe)
-- Return table with all arguments passed by 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 args = {} -- arguments passed to template
for k,v in pframe:argumentPairs() do
args[k] = v
end
args.in_text = args[1]
args.value = require_number(args.in_text, 'Need value', 'Value "%s" must be a number')
local in_unit = args[2]
local i = 3
local range = range_types[in_unit]
if range ~= nil then
args.in_text2 = args[3]
args.value2 = require_number(args.in_text2, 'Need second value', 'Second value "%s" must be a number')
in_unit = args[4]
i = 5
end
local out_unit = args[i]
local round_to = args[i+1]
if in_unit == nil then error('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 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)
-- Convert given invalue using parms (return '' if invalue == nil).
-- Return rounded, formatted string for result, using rounding
-- specified in parms.
-- 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 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.
round_to = require_integer(round_to, 'Need value', 'round_to "%s" must be an integer')
elseif sigfig then
-- Ignore disp.
sigfig = require_integer(sigfig, 'Need value', 'sigfig "%s" must be an integer')
if sigfig <= 0 then
msg = 'sigfig "%s" must be positive'
error(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
local fmt = '%.' .. string.format('%.0f', 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.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
-- TODO Not satisfactory? Should limit sigfigs?
text = string.format('%f', outvalue)
end
end
end
return 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)
-- If we can convert from given in to out unit, return the table values for the two given unit types.
parms.in_unit_table = units:lookup(parms.in_unit)
if parms.out_unit == nil then -- need to catch empty string also?
parms.out_unit = parms.in_unit_table.defaultunit
end
parms.out_unit_table = units:lookup(parms.out_unit)
if parms.in_unit_table.utype ~= parms.out_unit_table.utype then
local msg = 'Cannot convert %s to %s'
error(msg:format(parms.in_unit_table.utype, parms.out_unit_table.utype))
end
local intext = parms.in_text
local intext2 = parms.in_text2
local outext = cvtround(parms.value, intext, parms)
local outext2 = cvtround(parms.value2, intext2, parms)
local range = parms.range
local disp = parms.disp
local wikitext
intext = withseparator(intext) -- TODO what if intext already has commas?
if range == nil then
wikitext = disp_single[disp] or disp_single['b']
wikitext = wikitext:format(intext, parms.in_unit, outext, parms.out_unit)
else
wikitext = disp_double[disp] or disp_double['b']
wikitext = wikitext:format(intext, range[1], intext2, parms.in_unit, outext, range[2], outext2, parms.out_unit)
end
return 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 = get_parms(pframe)
local state,text = pcall(process, parms)
if not state 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