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A helper module to find the most specific chronology portal which actually exists for a given year or decade. Used to simplify linking to a chronology portal.
- October 2019 update
All by-year and by-century portals have been deleted. There are now only 8 decade portals, listed in Category:Decades portals.
So all checking for century and year portals has been disabled.
If any of the decade portals are deleted, then this module should be edited to remove that decade from the table existingDecadePortals
Parameters
editTakes one parameter, which must be either a year (e.g. "1879", "1123") or a decade (e.g. "1940s", "730s").
If the parameter is missing, empty, or does not fit the required format, an empty string is returned.
Output
editIf a portal is found, returns its name without the namespace prefix, e.g.
- for "Portal:1980s" return
1980s
- for "Portal:19th century" return
19th century
If no portal is found, it returns an empty string.
Usage
edit- Year parameter
{{#invoke: FindYDCportal | findydcportal |YYYY}}
... where YYYY
is a 3- or 4-digit year
- Decade parameter
{{#invoke: FindYDCportal | findydcportal |YYY0s}}
... where YYY0s
is a 3- or 4-digit decade
Examples
edit- Years
{{#invoke: FindYDCportal | findydcportal |2018}}
→ 2010s{{#invoke: FindYDCportal | findydcportal |1935}}
→{{#invoke: FindYDCportal | findydcportal |1857}}
→{{#invoke: FindYDCportal | findydcportal |736}}
→{{#invoke: FindYDCportal | findydcportal |1800}}
→
- Decades
{{#invoke: FindYDCportal | findydcportal |2000s}}
→ 2000s{{#invoke: FindYDCportal | findydcportal |1940s}}
→{{#invoke: FindYDCportal | findydcportal |560s}}
→
- Missing parameter
{{#invoke: FindYDCportal | findydcportal}}
→
- Empty parameter
{{#invoke: FindYDCportal | findydcportal | }}
→
- Invalid parameter
{{#invoke: FindYDCportal | findydcportal | 1927-related}}
→{{#invoke: FindYDCportal | findydcportal | Swedish chef}}
→
Logic
editIf the parameter is a year:
- If the year portal exists, return its name.
Otherwise try the decade. - If the decade portal exists, return its name.
Otherwise try the century - If the century portal exists, return its name.
Otherwise return an empty string
If the parameter is a decade:
- If the decade portal exists, return its name.
Otherwise try the century - If the century portal exists, return its name.
Otherwise return an empty string
See also
edit--[[
For a given 3- or 4-digit year or decade, find the most specific portal
which actually exists.
Takes one parameter, which must be either a year (e.g. "1879", "1123")
or a decade (e.g. "1940s", "790s").
If a portal is found, return its name without the namespace prefix
(e.g. for "Portal:1980s" return "1980s"); otherwise return an empty string.
If the parameter is missing, empty, or does not fit the required format,
an empty string is returned"
]]
local p = {}
-- This table of existing decade portals is the first check of whether a portal
-- exists for a given decade.
-- If the decade is listed in this table, then a system call is made to verify its existence
-- This approach has two advantages:
-- 1/ It reduces server load by reducing the number of expensive system calls
-- 2/ It avoids creating backlinks to non-existing portals, because a each .exists check
-- generates a backlink
local existingDecadePortals = {
["1920s"] = true,
["1930s"] = true,
["1940s"] = true,
["1950s"] = true,
["1960s"] = true,
["1970s"] = true,
["1980s"] = true,
["1990s"] = true
}
-- check for the existence of a portal with the given name
-- if it exists, returns the name
-- otherwise returns nil
function doesPortalExist(portalName)
local portalPage = mw.title.new( portalName, "Portal" )
if (portalPage.exists) then
return portalName
end
return nil
end
-- check for the existence of a portal with the name of that year
-- if it exists, returns the year
-- otherwise calls decadeCheck, and returns that result
-- otherwise returns nil
function checkYear(yearParam)
--[[
the year portals have all been deleted, so comment out this section
if doesPortalExist(yearParam) then
return yearParam
end
]]--
-- myDecade = the year, with the last digit stripped
-- e.g. "1694" → "1690"
-- Note that a decade is written as usul=ally written "YYY0s"
local myDecade = mw.ustring.gsub(yearParam, "%d$", "")
return checkDecade(myDecade)
end
-- check for the existence of a portal with the name of that decade
-- if it exists, returns the year
-- otherwise calls decadeCheck, and returns that result
-- otherwise returns nil
function checkDecade(decadeParam)
local mydecade = decadeParam .. "0s"
if (existingDecadePortals[mydecade] == true) then
if doesPortalExist(mydecade) then
return mydecade
end
end
-- We don't have a portal for the decade, so now try the century.
--[[
the century portals have all been deleted, so comment out this section
local myCenturyString = mw.ustring.gsub(decadeParam, "%d$", "")
local myCenturyNum = tonumber(myCenturyString)
local myCenturyNum = tonumber(myCenturyString)
-- increment by one, because we have now conveted e.g. "1870s" to "18"
-- but that's the 19th century
myCenturyNum = myCenturyNum + 1
-- the century portals have all been deleted, so disable the centeury checking
-- return checkCentury(tostring(myCenturyNum))
]]-- return ""
end
-- check for the existence of a portal with the name of that century
-- if it exists, returns the century
-- otherwise returns an empty string
function checkCentury(centuryParam)
local myCenturyString = ordinal_numbers(centuryParam) .. " century"
if doesPortalExist(myCenturyString) then
return myCenturyString
end
return ""
end
-- converts a string number to an string ordinal
-- e.g. 21 → 21st
-- 17 → 17th
-- code copied from https://stackoverflow.com/questions/20694133/how-to-to-add-th-or-rd-to-the-date (license:CC BY-SA 3.0 )
function ordinal_numbers(n)
local ordinal, digit = {"st", "nd", "rd"}, string.sub(n, -1)
if tonumber(digit) > 0 and tonumber(digit) <= 3 and string.sub(n,-2) ~= 11 and string.sub(n,-2) ~= 12 and string.sub(n,-2) ~= 13 then
return n .. ordinal[tonumber(digit)]
else
return n .. "th"
end
end
function trim(s)
return s:match "^%s*(.-)%s*$"
end
function p.findydcportal(frame)
-- Expects one parameter
-- {{{1}}} = a 3- or 4-digit year or deacde
-- e.g. 1916
-- 1504
-- 1630s
-- 920s
local arg1 = frame.args[1]
if arg1 == nil then
return ""
end
arg1 = trim(arg1) -- strip leading and trailing spaces
if (mw.ustring.match(arg1, "^%d%d%d%d?$")) then
-- it's a 3- or 4-digit-year
return checkYear(arg1)
elseif (mw.ustring.match(arg1, "^%d%d%d?0s$")) then
-- it's a 3- or 4-digit decade
-- so strip the trailing "0s"
local decadeArg = mw.ustring.gsub(arg1, "0s$", "")
return checkDecade(decadeArg)
end
-- If we get here, then arg1 was neither a year nor a decade
-- This is going to be a helper template, and diagnostics woud be intrusive
-- So just return an empty string
return ""
end
return p