return wikidata_code[operation](wikidata_data, ...)
end
local success, status, result = pcall(worker, ...)
if success then
return status, result
end
if parms.opt_sortable_debug then
-- Use debug=yes to crash if an error while accessing Wikidata.
error('Error accessing Wikidata: ' .. status, 0)
end
return false, { 'cvt_wd_fail' }
end  
local function get_parms(parms, args)
-- If successful, update parms and return true, unit where
-- parms is a table of all arguments passed to the template
-- converted to named arguments, and
-- unit is the input unit table;
-- or return false, t where t is an error message table.
-- For special processing (not a convert), can also return
-- true, wikitext where wikitext is the final result.
-- The returned input unit table may be for a fake unit using the specified
-- unit code as the symbol and name, and with bad_mcode = message code table.
-- MediaWiki removes leading and trailing whitespace from the values of
-- named arguments. However, the values of numbered arguments include any
-- whitespace entered in the template, and whitespace is used by some
-- parameters (example: the numbered parameters associated with "disp=x").
local kv_pairs = {} -- table of input key:value pairs where key is a name; needed because cannot iterate parms and add new fields to it
for k, v in pairs(args) do
if type(k) == 'number' or k == 'test' then -- parameter "test" is reserved for testing and is not translated
parms[k] = v
else
kv_pairs[k] = v
end
end
if parms.test == 'wikidata' then
local ulookup = function (ucode)
-- Use empty table for parms so it does not accumulate results when used repeatedly.
return lookup({}, ucode, 'no_combination')
end
return wikidata_call(parms, '_listunits', ulookup)
end
local success, msg = translate_parms(parms, kv_pairs)
if not success then return false, msg end
if parms.input then
success, msg = wikidata_call(parms, '_adjustparameters', parms, 1)
if not success then return false, msg end
end
local success, i, in_unit, in_unit_table = simple_get_values(parms)
if not success then
if type(i) == 'string' and i:match('^NNN+$') then
-- Some infoboxes have examples like (3 or more "N").
-- Output an empty string for these.
return false, { 'cvt_no_output' }
end
local valinfo
success, valinfo, i = get_values(parms)
if not success then return false, valinfo end
in_unit = strip(parms[i])
i = i + 1
success, in_unit_table = lookup(parms, in_unit, 'no_combination')
if not success then
in_unit = in_unit or ''
if parms.opt_ignore_error then -- display given unit code with no error (for use with )
in_unit_table = '' -- suppress error message and prevent processing of output unit
end
in_unit_table = setmetatable({
symbol = in_unit, name2 = in_unit, utype = in_unit,
scale = 1, default = *, defkey = *, linkey = '',
bad_mcode = in_unit_table }, unit_mt)
end
in_unit_table.valinfo = valinfo
end
if parms.test == 'msg' then
-- Am testing the messages produced when no output unit is specified, and
-- the input unit has a missing or invalid default.
-- Set two units for testing that.
-- LATER: Remove this code.
if in_unit == 'chain' then
in_unit_table.default = nil -- no default
elseif in_unit == 'rd' then
in_unit_table.default = "ft!X!m" -- an invalid expression
end
end
in_unit_table.inout = 'in' -- this is an input unit
if not parms.range then
local success, inext, composite_unit = get_composite(parms, i, in_unit_table)
if not success then return false, inext end
if composite_unit then
in_unit_table = composite_unit
i = inext
end
end
if in_unit_table.builtin == 'mach' then
-- As with old template, a number following Mach as the input unit is the altitude.
-- That is deprecated: should use altitude_ft=NUMBER or altitude_m=NUMBER.
local success, info
success = tonumber(parms[i]) -- this will often work and will give correct result for values like 2e4 without forcing output scientific notation
if success then
info = { value = success }
else
success, info = extract_number(parms, parms[i], false, true)
end
if success then
i = i + 1
in_unit_table.altitude = info.value
end
end
local word = strip(parms[i])
i = i + 1
local precision, is_bad_precision
local function set_precision(text)
local number, is_integer = get_number(text)
if number then
if is_integer then
precision = number
else
precision = text
is_bad_precision = true
end
return true -- text was used for precision, good or bad
end
end
if word and not set_precision(word) then
parms.out_unit = parms.out_unit or word
if set_precision(strip(parms[i])) then
i = i + 1
end
end
if parms.opt_adj_mid then
word = parms[i]
i = i + 1
if word then -- mid-text words
if word:sub(1, 1) == '-' then
parms.mid = word
else
parms.mid = ' ' .. word
end
end
end
if parms.opt_one_preunit then
parms[parms.opt_flip and 'preunit2' or 'preunit1'] = preunits(1, parms[i])
i = i + 1
end
if parms.disp == 'x' then
-- Following is reasonably compatible with the old template.
local first = parms[i] or ''
local second = parms[i+1] or ''
i = i + 2
if strip(first) == '' then -- user can enter '&#32;' rather than ' ' to avoid the default
first = ' [&nbsp;' .. first
second = '&nbsp;]' .. second
end
parms.joins = { first, second }
elseif parms.opt_two_preunits then
local p1, p2 = preunits(2, parms[i], parms[i+1])
i = i + 2
if parms.preunit1 then
-- To simplify documentation, allow unlikely use of adj=pre with disp=preunit
-- (however, an output unit must be specified with adj=pre and with disp=preunit).
parms.preunit1 = parms.preunit1 .. p1
parms.preunit2 = p2
else
parms.preunit1, parms.preunit2 = p1, p2
end
end
if precision == nil then
if set_precision(strip(parms[i])) then
i = i + 1
end
end
if is_bad_precision then
add_warning(parms, 1, 'cvt_bad_prec', precision)
else
parms.precision = precision
end
for j = i, i + 3 do
local parm = parms[j] -- warn if find a non-empty extraneous parameter
if parm and parm:match('%S') then
add_warning(parms, 1, 'cvt_unknown_option', parm)
break
end
end
return true, in_unit_table
end  
local function record_default_precision(parms, out_current, precision)
-- If necessary, adjust parameters and return a possibly adjusted precision.
-- When converting a range of values where a default precision is required,
-- that default is calculated for each value because the result sometimes
-- depends on the precise input and output values. This function may cause
-- the entire convert process to be repeated in order to ensure that the
-- same default precision is used for each individual convert.
-- If that were not done, a range like 1000 to 1000.4 may give poor results
-- because the first output could be heavily rounded, while the second is not.
-- For range 1000.4 to 1000, this function can give the second convert the
-- same default precision that was used for the first.
if not parms.opt_round_each then
local maxdef = out_current.max_default_precision
if maxdef then
if maxdef < precision then
parms.do_convert_again = true
out_current.max_default_precision = precision
else
precision = out_current.max_default_precision
end
else
out_current.max_default_precision = precision
end
end
return precision
end  
local function default_precision(parms, invalue, inclean, denominator, outvalue, in_current, out_current, extra)
-- Return a default value for precision (an integer like 2, 0, -2).
-- If denominator is not nil, it is the value of the denominator in inclean.
-- Code follows procedures used in old template.
local fudge = 1e-14 -- adds this, so we do too
local prec, minprec, adjust
local subunit_ignore_trailing_zero
local subunit_more_precision -- kludge for "in" used in input like "|2|ft|6|in"
local composite = in_current.composite
if composite then
subunit_ignore_trailing_zero = true -- input "|2|st|10|lb" has precision 0, not -1
if composite[#composite].exception == 'subunit_more_precision' then
subunit_more_precision = true -- do not use standard precision with input like "|2|ft|6|in"
end
end
if denominator and denominator > 0 then
prec = math.max(log10(denominator), 1)
else