>Tom.Reding: Improve readability of long, compound if-statements

2024-02-24T03:12:47Z

Improve readability of long, compound if-statements

New page

POINT_IN_TIME_PID = "P585"
YT_CHAN_ID_PID= "P2397"
SUB_COUNT_PID = "P8687"

local p = {}

-- taken from https://en.wikipedia.org/wiki/Module:Wd
function parseDate(dateStr, precision)
precision = precision or "d"

local i, j, index, ptr
local parts = {nil, nil, nil}

if dateStr == nil then
return parts[1], parts[2], parts[3] -- year, month, day
end

-- 'T' for snak values, '/' for outputs with '/Julian' attached
i, j = dateStr:find("[T/]")

if i then
dateStr = dateStr:sub(1, i-1)
end

local from = 1

if dateStr:sub(1,1) == "-" then
-- this is a negative number, look further ahead
from = 2
end

index = 1
ptr = 1

i, j = dateStr:find("-", from)

if i then
-- year
parts[index] = tonumber(mw.ustring.gsub(dateStr:sub(ptr, i-1), "^%+(.+)$", "%1"), 10) -- remove '+' sign (explicitly give base 10 to prevent error)

if parts[index] == -0 then
parts[index] = tonumber("0") -- for some reason, 'parts[index] = 0' may actually store '-0', so parse from string instead
end

if precision == "y" then
-- we're done
return parts[1], parts[2], parts[3] -- year, month, day
end

index = index + 1
ptr = i + 1

i, j = dateStr:find("-", ptr)

if i then
-- month
parts[index] = tonumber(dateStr:sub(ptr, i-1), 10)

if precision == "m" then
-- we're done
return parts[1], parts[2], parts[3] -- year, month, day
end

index = index + 1
ptr = i + 1
end
end

if dateStr:sub(ptr) ~= "" then
-- day if we have month, month if we have year, or year
parts[index] = tonumber(dateStr:sub(ptr), 10)
end

return parts[1], parts[2], parts[3] -- year, month, day
end

-- taken from https://en.wikipedia.org/wiki/Module:Wd
local function datePrecedesDate(aY, aM, aD, bY, bM, bD)
if aY == nil or bY == nil then
return nil
end
aM = aM or 1
aD = aD or 1
bM = bM or 1
bD = bD or 1

if aY < bY then
return true
elseif aY > bY then
return false
elseif aM < bM then
return true
elseif aM > bM then
return false
elseif aD < bD then
return true
end

return false
end

function getClaimDate(claim)
if claim['qualifiers'] and claim['qualifiers'][POINT_IN_TIME_PID] then
local pointsInTime = claim['qualifiers'][POINT_IN_TIME_PID]
if #pointsInTime ~= 1 then
-- be conservative in what we accept
error("Encountered a statement with zero or multiple point in time (P85) qualifiers. Please add or remove point in time information so each statement has exactly one")
end
local pointInTime = pointsInTime[1]
if pointInTime and
pointInTime['datavalue'] and
pointInTime['datavalue']['value'] and
pointInTime['datavalue']['value']['time']
then
return parseDate(pointInTime['datavalue']['value']['time'])
end
end
return nil
end

-- for a given list of statements find the newest one with a matching qual
function newestMatchingStatement(statements, qual, targetQualValue)
local newestStatement = nil
local newestStatementYr = nil
local newestStatementMo = nil
local newestStatementDay = nil
for k, v in pairs(statements) do
if v['rank'] ~= "deprecated" and v['qualifiers'] and v['qualifiers'][qual] then
local quals = v['qualifiers'][qual]
-- should only have one instance of the qualifier on a statement
if #quals == 1 then
local qual = quals[1]
if qual['datavalue'] and qual['datavalue']['value'] then
local qualValue = qual['datavalue']['value']
if qualValue == targetQualValue then
local targetYr, targetMo, targetDay = getClaimDate(v)
if targetYr then
local older = datePrecedesDate(targetYr, targetMo, targetDay, newestStatementYr, newestStatementMo, newestStatementDay)
if older == nil or not older then
newestStatementYr, newestStatementMo, newestStatementDay = targetYr, targetMo, targetDay
newestStatement = v
end
end
end
end
end
end
end
return newestStatement
end

-- for a given property and qualifier pair returns the newest statement that matches
function newestMatching(e, prop, qual, targetQualValue)
-- first check the best statements
local statements = e:getBestStatements(prop)
local newestStatement = newestMatchingStatement(statements, qual, targetQualValue)
if newestStatement then
return newestStatement
end
-- try again with all statements if nothing so far
statements = e:getAllStatements(prop)
newestStatement = newestMatchingStatement(statements, qual, targetQualValue)
if newestStatement then
return newestStatement
end
return nil
end

function getEntity ( frame )
local qid = nil
if frame.args then
qid = frame.args["qid"]
end
if not qid then
qid = mw.wikibase.getEntityIdForCurrentPage()
end
if not qid then
local e = nil
return e
end
local e = mw.wikibase.getEntity(qid)
assert(e, "No such item found: " .. qid)
return e
end

-- find the channel ID we are going to be getting the sub counts for
function getBestYtChanId(e)
local chanIds = e:getBestStatements(YT_CHAN_ID_PID)
if #chanIds == 1 then
local chan = chanIds[1]
if chan and
chan["mainsnak"] and
chan["mainsnak"]["datavalue"] and
chan["mainsnak"]["datavalue"]["value"]
then
return chan["mainsnak"]["datavalue"]["value"]
end
end
return nil
end

function returnError(frame, eMessage)
return frame:expandTemplate{ title = 'error', args = { eMessage } } .. "[[Category:Pages with YouTubeSubscribers module errors]]"
end

-- the date of the current YT subscriber count
function p.date( frame )
local e = getEntity(frame)
assert(e, "No qid found for page. Please make a Wikidata item for this article")
local chanId = getBestYtChanId(e)
assert(chanId, "Could not find a single best YouTube channel ID for this item. Add a YouTube channel ID or set the rank of one channel ID to be preferred")
local s = newestMatching(e, SUB_COUNT_PID, YT_CHAN_ID_PID, chanId)
if s then
local yt_year, yt_month, yt_day = getClaimDate(s)
if not yt_year then
return nil
end
local dateString = yt_year .. "|"
-- construct YYYY|mm|dd date string
if yt_month and yt_month ~= 0 then
dateString = dateString .. yt_month .. "|"
-- truncate the day of month
--if yt_day and yt_day ~= 0 then
-- dateString = dateString .. yt_day
--end
end
return frame:expandTemplate{title="Format date", args = {yt_year, yt_month, yd_day}}
end
error("Could not find a date for YouTube subscriber information. Is there a social media followers statement (P8687) qualified with good values for P585 and P2397?")
end

function p.dateNice( frame )
local status, obj = pcall(p.date, frame)
if status then
return obj
else
return returnError(frame, obj)
end
end

-- the most up to date number of subscribers
function p.subCount( frame )
local subCount = nil
local e = getEntity(frame)
if not e then
subCount = -424
return tonumber(subCount)
end
local chanId = getBestYtChanId(e)
if chanId then
local s = newestMatching(e, SUB_COUNT_PID, YT_CHAN_ID_PID, chanId)
if s and
s["mainsnak"] and
s['mainsnak']["datavalue"] and
s['mainsnak']["datavalue"]["value"] and
s['mainsnak']["datavalue"]['value']['amount']
then
subCount = s['mainsnak']["datavalue"]['value']['amount']
end
else
subCount = -404
end
if subCount then
return tonumber(subCount)
else
subCount = -412
return tonumber(subCount)
end
end

function p.subCountNice( frame )
local status, obj = pcall(p.subCount, frame)
if status then
if obj >= 0 then
return frame:expandTemplate{title="Format price", args = {obj}}
else
return obj
end
else
return returnError(frame, obj)
end
end

return p

Module:YouTubeSubscribers - Revision history

>Tom.Reding: Improve readability of long, compound if-statements