Module:Convert/wikidata
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Documentation for this module may be created at Module:Convert/wikidata/doc
-- Functions to access Wikidata for Module:Convert.
local Collection = {}
Collection.__index = Collection
do
function Collection:add(item)
if item ~= nil then
self.n = self.n + 1
self[self.n] = item
end
end
function Collection:join(sep)
return table.concat(self, sep)
end
function Collection:remove(pos)
if self.n > 0 and (pos == nil or (0 < pos and pos <= self.n)) then
self.n = self.n - 1
return table.remove(self, pos)
end
end
function Collection:sort(comp)
table.sort(self, comp)
end
function Collection.new()
return setmetatable({n = 0}, Collection)
end
end
local function strip_to_nil(text)
-- If text is a non-empty string, return its trimmed content,
-- otherwise return nothing (empty string or not a string).
if type(text) == 'string' then
return text:match('(%S.-)%s*$')
end
end
local function frequency_unit(value, unit_table)
-- For use when converting m to Hz.
-- Return true, s where s = name of unit's default output unit,
-- or return false, t where t is an error message table.
-- However, for simplicity a valid result is always returned.
local unit
if unit_table._symbol == 'm' then
-- c = speed of light in a vacuum = 299792458 m/s
-- frequency = c / wavelength
local w = value * (unit_table.scale or 1)
local f = 299792458 / w -- if w == 0, f = math.huge which works here
if f >= 1e12 then
unit = 'THz'
elseif f >= 1e9 then
unit = 'GHz'
elseif f >= 1e6 then
unit = 'MHz'
elseif f >= 1e3 then
unit = 'kHz'
else
unit = 'Hz'
end
end
return true, unit or 'Hz'
end
local function wavelength_unit(value, unit_table)
-- Like frequency_unit but for use when converting Hz to m.
local unit
if unit_table._symbol == 'Hz' then
-- Using 0.9993 rather than 1 avoids rounding which would give results
-- like converting 300 MHz to 100 cm instead of 1 m.
local w = 1 / (value * (unit_table.scale or 1)) -- Hz scale is inverted
if w >= 0.9993e6 then
unit = 'Mm'
elseif w >= 0.9993e3 then
unit = 'km'
elseif w >= 0.9993 then
unit = 'm'
elseif w >= 0.9993e-2 then
unit = 'cm'
elseif w >= 0.9993e-3 then
unit = 'mm'
else
unit = 'um'
end
end
return true, unit or 'm'
end
local specials = {
frequency = { frequency_unit },
wavelength = { wavelength_unit },
--------------------------------------------------------------------------------
-- Following is a removed experiment to show two values as a range
-- using '-' as the separator.
-- frequencyrange = { frequency_unit, '-' },
-- wavelengthrange = { wavelength_unit, '-' },
}
local function make_unit(units, parms, uid)
-- Return a unit code for convert or nil if unit unknown.
-- If necessary, add a dummy unit to parms so convert will use it
-- for the input without attempting a conversion since nothing
-- useful is available (for example, with unit volt).
local unit = units[uid]
if type(unit) ~= 'table' then
return nil
end
local ucode = unit.ucode
if ucode and not unit.si then
return ucode -- a unit known to convert
end
parms.opt_ignore_error = true
ucode = ucode or unit._ucode -- must be a non-empty string
local ukey, utable
if unit.si then
local base = units[unit.si]
ukey = base.symbol -- must be a non-empty string
local n1 = base.name1
local n2 = base.name2
if not n1 then
n1 = ukey
n2 = n2 or n1 -- do not append 's'
end
utable = {
_symbol = ukey,
_name1 = n1,
_name2 = n2,
link = unit.link or base.link,
utype = n1,
prefixes = 1,
}
else
ukey = ucode
utable = {
symbol = ucode, -- must be a non-empty string
name1 = unit.name1, -- if nil, uses symbol
name2 = unit.name2, -- if nil, uses name1..'s'
link = unit.link, -- if nil, uses name1
utype = unit.name1 or ucode,
}
end
utable.scale = 1
utable.default = ''
utable.defkey = ''
utable.linkey = ''
utable.bad_mcode = ''
parms.unittable = { [ukey] = utable }
return ucode
end
local function matches_qualifier(statement, qual)
-- Return:
-- false, nil : if statement does not match specification
-- true, nil : if matches, and statement has no qualifier
-- true, sq : if matches, where sq is the statement's qualifier
-- A match means that no qualifier was specified (qual == nil), or that
-- the statement has a qualifier matching the specification.
-- If a match occurs, the caller needs the statement's qualifier (if any)
-- so statements that duplicate the qualifier are not used, after the first.
-- Then, if convert is showing all values for a property such as the diameter
-- of a telescope's mirror (diameters of primary and secondary mirrors), it
-- will not show alternative values that could in principle be present for the
-- same item (telescope) and property (diameter) and qualifier (primary/secondary).
local target = (statement.qualifiers or {}).P518 -- P518 is "applies to part"
if type(target) == 'table' then
for _, q in ipairs(target) do
if type(q) == 'table' then
local value = (q.datavalue or {}).value
if value then
if qual == nil or qual == value.id then
return true, value.id
end
end
end
end
end
if qual == nil then
return true, nil -- only occurs if statement has no qualifier
end
return false, nil -- statement's qualifier is not relevant because statement will be skipped
end
local function get_statements(parms, pid)
-- Get specified item and return a list of tables with each statement for property pid.
-- Each table is of form {statqual=sq, stmt=statement} where sq = statement qualifier (nil if none).
-- Statements are in Wikidata's order except that those with preferred rank
-- are first, then normal rank. Any other rank is ignored.
local stored = {} -- qualifiers of statements that are first for the qualifier, and will be returned
local qid = strip_to_nil(parms.qid) -- nil for current page's item, or an item id (expensive)
local qual = strip_to_nil(parms.qual) -- nil or id of wanted P518 (applies to part) item in qualifiers
local result = Collection.new()
local entity = mw.wikibase.getEntity(qid)
if type(entity) == 'table' then
local statements = (entity.claims or {})[pid]
if type(statements) == 'table' then
for _, rank in ipairs({ 'preferred', 'normal' }) do
for _, statement in ipairs(statements) do
if type(statement) == 'table' and rank == statement.rank then
local is_match, statqual = matches_qualifier(statement, qual)
if is_match then
result:add({ statqual = statqual, stmt = statement })
end
end
end
end
end
end
return result
end
local function input_from_property(tdata, parms, pid)
-- Given that pid is a Wikidata property identifier like 'P123',
-- return a collection of {amount, ucode} pairs (two strings)
-- for each matching item/property, or return nothing.
--------------------------------------------------------------------------------
-- There appear to be few restrictions on how Wikidata is organized so it is
-- very likely that any decision a module makes about how to handle data
-- will be wrong for some cases at some time. This meets current requirements.
-- For each qualifier (or if no qualifier), if there are any preferred
-- statements, use them and ignore any normal statements.
-- For each qualifier, for the preferred statements if any, or for
-- the normal statements (but not both):
-- * Accept each statement if it has no qualifier (this will not occur
-- if qual=x is specified because other code already ensures that in that
-- case, only statements with a qualifier matching x are considered).
-- * Ignore any statements after the first if it has a qualifier.
-- The rationale is that for the diameter at [[South Pole Telescope]], want
-- convert to show the diameters for both the primary and secondary mirrors
-- if the convert does not specify which diameter is wanted.
-- However, if convert is given the wanted qualifier, only one value
-- (_the_ diameter) is wanted. For simplicity/consistency, that is also done
-- even if no qual=x is specified. Unclear what should happen.
-- For the wavelength at [[Nançay Radio Telescope]], want to show all three
-- values, and the values have no qualifiers.
--------------------------------------------------------------------------------
local result = Collection.new()
local done = {}
local skip_normal
for _, t in ipairs(get_statements(parms, pid)) do
local statement = t.stmt
if statement.mainsnak and statement.mainsnak.datatype == 'quantity' then
local value = (statement.mainsnak.datavalue or {}).value
if value then
local amount = value.amount
if amount then
amount = tostring(amount) -- in case amount is ever a number
if amount:sub(1, 1) == '+' then
amount = amount:sub(2)
end
local unit = value.unit
if type(unit) == 'string' then
unit = unit:match('Q%d+$') -- unit item id is at end of URL
local ucode = make_unit(tdata.wikidata_units, parms, unit)
if ucode then
local skip
if t.statqual then
if done[t.statqual] then
skip = true
else
done[t.statqual] = true
end
else
if statement.rank == 'preferred' then
skip_normal = true
elseif skip_normal then
skip = true
end
end
if not skip then
result:add({ amount, ucode })
end
end
end
end
end
end
end
return result
end
local function input_from_text(tdata, parms, text, insert2)
-- Given string should be of form "<value><space><unit>" or
-- "<value1><space>ft<space><value2><space>in" for a special case (feet and inches).
-- Return true if values/units were extracted and inserted, or return nothing.
text = text:gsub(' ', ' '):gsub('%s+', ' ')
local pos = text:find(' ', 1, true)
if pos then
-- Leave checking of value to convert which can handle fractions.
local value = text:sub(1, pos - 1)
local uid = text:sub(pos + 1)
if uid:sub(1, 3) == 'ft ' and uid:sub(-3) == ' in' then
-- Special case for enwiki to allow {{convert|input=5 ft 10+1/2 in}}
insert2(uid:sub(4, -4), 'in')
insert2(value, 'ft')
else
insert2(value, make_unit(tdata.wikidata_units, parms, uid) or uid)
end
return true
end
end
local function adjustparameters(tdata, parms, index)
-- For Module:Convert, adjust parms (a table of {{convert}} parameters).
-- Return true if successful or return false, t where t is an error message table.
-- This is intended mainly for use in infoboxes where the input might be
-- <value><space><unit> or
-- <wikidata-property-id>
-- If successful, insert values and units in parms, before given index.
local text = parms.input -- should be a trimmed, non-empty string
local pid = text:match('^P%d+$')
local sep = ','
local special = specials[parms[index]]
if special then
parms.out_unit = special[1]
sep = special[2] or sep
table.remove(parms, index)
end
local function quit()
return false, pid and { 'cvt_no_output' } or { 'cvt_bad_input', text }
end
local function insert2(first, second)
table.insert(parms, index, second)
table.insert(parms, index, first)
end
if pid then
parms.input_text = '' -- output an empty string if an error occurs
local result = input_from_property(tdata, parms, pid)
if result.n == 0 then
return quit()
end
local ucode
for i, t in ipairs(result) do
-- Convert requires each input unit to be identical.
if i == 1 then
ucode = t[2]
elseif ucode ~= t[2] then
return quit()
end
end
local item = ucode
if item == parms[index] then
-- Remove specified output unit if it is the same as the Wikidata unit.
-- For example, {{convert|input=P2044|km}} with property "12 km".
table.remove(parms, index)
end
for i = result.n, 1, -1 do
insert2(result[i][1], item)
item = sep
end
return true
else
if input_from_text(tdata, parms, text, insert2) then
return true
end
end
return quit()
end
--------------------------------------------------------------------------------
--- List units and check syntax of definitions ---------------------------------
--------------------------------------------------------------------------------
local specifications = {
-- seq = sequence in which fields are displayed
base = {
title = 'SI base units',
fields = {
symbol = { seq = 2, mandatory = true },
name1 = { seq = 3, mandatory = true },
name2 = { seq = 4 },
link = { seq = 5 },
},
noteseq = 6,
header = '{| class="wikitable"\n!si !!symbol !!name1 !!name2 !!link !!note',
item = '|-\n|%s ||%s ||%s ||%s ||%s ||%s',
footer = '|}',
},
alias = {
title = 'Aliases for convert',
fields = {
ucode = { seq = 2, mandatory = true },
si = { seq = 3 },
},
noteseq = 4,
header = '{| class="wikitable"\n!alias !!ucode !!base !!note',
item = '|-\n|%s ||%s ||%s ||%s',
footer = '|}',
},
known = {
title = 'Units known to convert',
fields = {
ucode = { seq = 2, mandatory = true },
label = { seq = 3, mandatory = true },
},
noteseq = 4,
header = '{| class="wikitable"\n!qid !!ucode !!label !!note',
item = '|-\n|%s ||%s ||%s ||%s',
footer = '|}',
},
unknown = {
title = 'Units not known to convert',
fields = {
_ucode = { seq = 2, mandatory = true },
si = { seq = 3 },
name1 = { seq = 4 },
name2 = { seq = 5 },
link = { seq = 6 },
label = { seq = 7, mandatory = true },
},
noteseq = 8,
header = '{| class="wikitable"\n!qid !!_ucode !!base !!name1 !!name2 !!link !!label !!note',
item = '|-\n|%s ||%s ||%s ||%s ||%s ||%s ||%s ||%s',
footer = '|}',
},
}
local function listunits(tdata, ulookup)
-- For Module:Convert, make wikitext to list the built-in Wikidata units.
-- Return true, wikitext if successful or return false, t where t is an
-- error message table. Currently, an error return never occurs.
-- The syntax of each unit definition is checked and a note is added if
-- a problem is detected.
local function safe_cells(t)
-- This is not currently needed, but in case definitions ever use wikitext
-- like '[[kilogram|kg]]', escape the text so it works in a table cell.
local result = {}
for i, v in ipairs(t) do
if v:find('|', 1, true) then
v = v:gsub('(%[%[[^%[%]]-)|(.-%]%])', '%1\0%2') -- replace pipe in piped link with a zero byte
v = v:gsub('|', '|') -- escape '|'
v = v:gsub('%z', '|') -- restore pipe in piped link
end
result[i] = v:gsub('{', '{') -- escape '{'
end
return unpack(result)
end
local wdunits = tdata.wikidata_units
local speckeys = { 'base', 'alias', 'unknown', 'known' }
for _, sid in ipairs(speckeys) do
specifications[sid].units = Collection.new()
end
local keys = Collection.new()
for k, v in pairs(wdunits) do
keys:add(k)
end
table.sort(keys)
local note_count = 0
for _, key in ipairs(keys) do
local unit = wdunits[key]
local ktext, sid
if key:match('^Q%d+$') then
ktext = '[[d:' .. key .. '|' .. key .. ']]'
if unit.ucode then
sid = 'known'
else
sid = 'unknown'
end
elseif unit.ucode then
ktext = key
sid = 'alias'
else
ktext = key
sid = 'base'
end
local result = { ktext }
local spec = specifications[sid]
local fields = spec.fields
local note = Collection.new()
for k, v in pairs(unit) do
if fields[k] then
local seq = fields[k].seq
if result[seq] then
note:add('duplicate ' .. k) -- cannot happen since keys are unique
else
result[seq] = v
end
else
note:add('invalid ' .. k)
end
end
for k, v in pairs(fields) do
local value = result[v.seq]
if value then
if k == 'si' and not wdunits[value] then
note:add('need si ' .. value)
end
if k == 'label' then
local wdl = mw.wikibase.label(key)
if wdl ~= value then
note:add('label changed to ' .. tostring(wdl))
end
end
else
result[v.seq] = ''
if v.mandatory then
note:add('missing ' .. k)
end
end
end
local text
if note.n > 0 then
note_count = note_count + 1
text = '*' .. note:join('<br />')
end
result[spec.noteseq] = text or ''
spec.units:add(result)
end
local results = Collection.new()
if note_count > 0 then
local text = note_count .. (note_count == 1 and ' note' or ' notes')
results:add("'''Search for * to see " .. text .. "'''\n")
end
for _, sid in ipairs(speckeys) do
local spec = specifications[sid]
results:add("'''" .. spec.title .. "'''")
results:add(spec.header)
local fmt = spec.item
for _, unit in ipairs(spec.units) do
results:add(string.format(fmt, safe_cells(unit)))
end
results:add(spec.footer)
end
return true, results:join('\n')
end
return { _adjustparameters = adjustparameters, _listunits = listunits }