Module:palindromes

The following documentation is located at Module:palindromes/documentation. ^[edit]

Useful links: subpage list • links • transclusions • testcases • sandbox

---

local u = mw.ustring.char

local export = {}

local data = {
	["he"] = {
		from = {
			"[ם]",
			"[ן]",
			"[ך]",
			"[ף]",
			"[ץ]",
			"[" .. u(0x0591) .. "-" .. u(0x05BD) .. u(0x05BF) .. "-" .. u(0x05C5) .. u(0x05C7) .. "]"
		},
		to = {
			"מ",
			"נ",
			"כ", 
			"פ",
			"צ"
		}
	},
	["grc"] = {
		from = {"[ᾳάᾴὰᾲᾶᾷἀᾀἄᾄἂᾂἆᾆἁᾁἅᾅἃᾃἇᾇᾱᾰ]", "[ἈᾈἌᾌἊᾊἎᾎἉᾉἍᾍἋᾋἏᾏᾹᾸ]", "[έὲἐἔἒἑἕἓ]",
			"[ἘἜἚἙἝἛ]", "[ῃήῄὴῂῆῇἠᾐἤᾔἢᾒἦᾖἡᾑἥᾕἣᾓἧᾗ]", "[ἨᾘἬᾜἪᾚἮᾞἩᾙἭᾝἫᾛἯᾟ]",
			"[ίὶῖἰἴἲἶἱἵἳἷϊΐῒῗῑῐ]", "[ἸἼἺἾἹἽἻἿῙῘ]", "[όὸὀὄὂὁὅὃ]", "[ὈὌὊὉὍὋ]",
			"[ύὺῦὐὔὒὖὑὕὓὗϋΰῢῧῡῠ]", "[ὙὝὛὟῩῨ]", "[ῳώῴὼῲῶῷὠᾠὤᾤὢᾢὦᾦὡᾡὥᾥὣᾣὧᾧ]",
			"[ὨᾨὬᾬὪᾪὮᾮὩᾩὭᾭὫᾫὯᾯ]", "[ῥῤ]", "[Ῥ]", "[ς]", "[́͂]"},
		to = {"α", "Α", "ε", "Ε", "η", "Η", "ι", "Ι", "ο", "Ο", "υ", "Υ", "ω", "Ω", "ρ", "Ρ", "σ"}
	},
}

local function ignoreCharacters(term, lang)
	term = mw.ustring.lower(term)
	term = mw.ustring.gsub(term, "[ ,%.%?!%%%-'\"]", "")
	
	if data[lang:getCode()] then
		for i, from in ipairs(data[lang:getCode()].from) do
			term = mw.ustring.gsub(term, from, data[lang:getCode()].to[i] or "")
		end
	end
	
	return term
end

function export.is_palindrome(term, lang)
	-- Remove punctuation and casing
	term = ignoreCharacters(term, lang)
	
	-- Ignore terms consisting of less than 3 characters
	local n = mw.ustring.len(term)
	
	if (n <= 2) then
		return false
	end
	
	-- Ignore terms that consist of just one character repeated
	if term == mw.ustring.rep(mw.ustring.sub(term, 1, 1), n) then
		return false
	end
	
	local reversed = {}
	
	for c in mw.ustring.gmatch(term, ".") do
		table.insert(reversed, 1, c)
	end
	
	reversed = table.concat(reversed)
	
	if term == reversed then
		return true
	else
		return false
	end
end

return export