-- Convert a value from one unit of measurement to another.
-- Example: --> 123 pounds (56 kg)
-- See :en:Template:Convert/Transwiki guide if copying to another wiki.  
local MINUS = '−' -- Unicode U+2212 MINUS SIGN (UTF-8: e2 88 92)
local abs = math.abs
local floor = math.floor
local format = string.format
local log10 = math.log10
local ustring = mw.ustring
local ulen = ustring.len
local usub = ustring.sub  
-- Configuration options to keep magic values in one location.
-- Conversion data and message text are defined in separate modules.
local config, maxsigfig
local numdot -- must be '.' or ',' or a character which works in a regex
local numsep, numsep_remove, numsep_remove2
local data_code, all_units
local text_code
local varname -- can be a code to use variable names that depend on value
local from_en_table -- to translate an output string of en digits to local language
local to_en_table -- to translate an input string of digits in local language to en
-- Use translation_table in convert/text to change the following.
local en_default -- true uses lang=en unless convert has lang=local or local digits
local group_method = 3 -- code for how many digits are in a group
local per_word = 'per' -- for units like "liters per kilometer"
local plural_suffix = 's' -- only other useful value is probably '' to disable plural unit names
local omitsep -- true to omit separator before local symbol/name  
-- All units should be defined in the data module. However, to cater for quick changes
-- and experiments, any unknown unit is looked up in an extra data module, if it exists.
-- That module would be transcluded in only a small number of pages, so there should be
-- little server overhead from making changes, and changes should propagate quickly.
local extra_module -- name of module with extra units
local extra_units -- nil or table of extra units from extra_module  
-- Some options in the invoking template can set variables used later in the module.
local currency_text -- for a user-defined currency symbol: (euro replaces dollar)  
local function from_en(text)
-- Input is a string representing a number in en digits with '.' decimal mark,
-- without digit grouping (which is done just after calling this).
-- Return the translation of the string with numdot and digits in local language.
if numdot ~= '.' then
text = text:gsub('%.', numdot)
end
if from_en_table then
text = text:gsub('%d', from_en_table)
end
return text
end  
local function to_en(text)
-- Input is a string representing a number in the local language with
-- an optional numdot decimal mark and numsep digit grouping.
-- Return the translation of the string with '.' mark and en digits,
-- and no separators (they have to be removed here to handle cases like
-- numsep = '.' and numdot = ',' with input "1.234.567,8").
if to_en_table then
text = ustring.gsub(text, '%d', to_en_table)
end
if numsep_remove then
text = text:gsub(numsep_remove, '')
end
if numsep_remove2 then
text = text:gsub(numsep_remove2, '')
end
if numdot ~= '.' then
text = text:gsub(numdot, '.')
end
return text
end  
local function decimal_mark(text)
-- Return ',' if text probably is using comma for decimal mark, or has no decimal mark.
-- Return '.' if text probably is using dot for decimal mark.
-- Otherwise return nothing (decimal mark not known).
if not text:find('[.,]') then return ',' end
text = text:gsub('^%-', *):gsub('%+%d+/%d+$', *):gsub('[Ee]%-?%d+$', '')
local decimal =
text:match('^0?([.,])%d+$') or
text:match('%d([.,])%d?%d?$') or
text:match('%d([.,])%d%d%d%d+$')
if decimal then return decimal end
if text:match('%.%d+%.') then return ',' end
if text:match('%,%d+,') then return '.' end
end  
local add_warning, with_separator -- forward declarations
local function to_en_with_check(text, parms)
-- Version of to_en for a wiki using numdot = ',' and numsep = '.' to check
-- text (an input number as a string) which might have been copied from enwiki.
-- For example, in '1.234' the '.' could be a decimal mark or a group separator.
-- From viwiki.
if to_en_table then
text = ustring.gsub(text, '%d', to_en_table)
end
if decimal_mark(text) == '.' then
local original = text
text = text:gsub(',', '') -- for example, interpret "1,234.5" as an enwiki value
if parms then
add_warning(parms, 0, 'cvt_enwiki_num', original, with_separator({}, text))
end
else
if numsep_remove then
text = text:gsub(numsep_remove, '')
end
if numsep_remove2 then
text = text:gsub(numsep_remove2, '')
end
if numdot ~= '.' then
text = text:gsub(numdot, '.')
end
end
return text
end  
local function omit_separator(id)
-- Return true if there should be no separator before id (a unit symbol or name).
-- For zhwiki, there should be no separator if id uses local characters.
-- The following kludge should be a sufficient test.
if omitsep then
if id:sub(1, 2) == '-{' then -- for "-{...}-" content language variant
return true
end
if id:byte > 127 then
local first = usub(id, 1, 1)
if first ~= 'Å' and first ~= '°' and first ~= 'µ' then
return true
end
end
end
return id:sub(1, 1) == '/' -- no separator before units like "/ha"
end  
local spell_module -- name of module that can spell numbers
local speller -- function from that module to handle spelling (set if needed)
local wikidata_module, wikidata_data_module -- names of Wikidata modules
local wikidata_code, wikidata_data -- exported tables from those modules (set if needed)  
local function set_config(args)
-- Set configuration options from template #invoke or defaults.
config = args
maxsigfig = config.maxsigfig or 14 -- maximum number of significant figures
local data_module, text_module
local sandbox = config.sandbox and ('/' .. config.sandbox) or ''
data_module = "Module:Convert/data" .. sandbox
text_module = "Module:Convert/text" .. sandbox
extra_module = "Module:Convert/extra" .. sandbox
wikidata_module = "Module:Convert/wikidata" .. sandbox
wikidata_data_module = "Module:Convert/wikidata/data" .. sandbox
spell_module = "Module:ConvertNumeric"
data_code = mw.loadData(data_module)
text_code = mw.loadData(text_module)
all_units = data_code.all_units
local translation = text_code.translation_table
if translation then
numdot = translation.numdot
numsep = translation.numsep
if numdot == ',' and numsep == '.' then
if text_code.all_messages.cvt_enwiki_num then
to_en = to_en_with_check
end
end
if translation.group then
group_method = translation.group
end
if translation.per_word then
per_word = translation.per_word
end
if translation.plural_suffix then
plural_suffix = translation.plural_suffix
end
varname = translation.varname
from_en_table = translation.from_en
local use_workaround = true
if use_workaround then
-- 2013-07-05 workaround bug by making a copy of the required table.
-- mw.ustring.gsub fails with a table (to_en_table) as the replacement,
-- if the table is accessed via mw.loadData.
local source = translation.to_en
if source then
to_en_table = {}
for k, v in pairs(source) do
to_en_table[k] = v
end
end
else
to_en_table = translation.to_en
end
if translation.lang == 'en default' then
en_default = true -- for hiwiki
end
omitsep = translation.omitsep -- for zhwiki
end
numdot = config.numdot or numdot or '.' -- decimal mark before fractional digits
numsep = config.numsep or numsep or ',' -- group separator for numbers
-- numsep should be ',' or '.' or '' or '&nbsp;' or a Unicode character.
-- numsep_remove must work in a regex to identify separators to be removed.
if numsep ~= '' then
numsep_remove = (numsep == '.') and '%.' or numsep
end
if numsep ~= ',' and numdot ~= ',' then
numsep_remove2 = ',' -- so numbers copied from enwiki will work
end
end  
local function collection
-- Return a table to hold items.
return {
n = 0,
add = function (self, item)
self.n = self.n + 1
self[self.n] = item
end,
}
end  
local function divide(numerator, denominator)
-- Return integers quotient, remainder resulting from dividing the two
-- given numbers, which should be unsigned integers.