「モジュール:文字列」を編集中

local p = {}

function p.bytenum(frame)
	return string.len(frame.args[1])
end

function p.emcharnum(frame)
	return string.len(frame.args[1]) / 3
end

function p.each_utf8(frame)
	local i = 1
	str = frame.args[1]
	if i > #str then
		return
	end
	local b = string.byte(frame.args[1],i)
	if b == 0 then
		return
	elseif b < 128 then
		local m = string.sub(frame.args[1],i,i)
		i = i + 1
		return m
	elseif b < 192 then
		assert(false,"invalid byte")
		return
	elseif b < 224 then
		local m = string.sub(frame.args[1],i,i+1)
		i = i + 2
		return m
	elseif b < 240 then
		local m = string.sub(frame.args[1],i,i+2)
		i = i + 3
		return m
	elseif b < 248 then
		local m = string.sub(frame.args[1],i,i+3)
		i = i + 4
		return m
	elseif b < 252 then
		local m = string.sub(frame.args[1],i,i+4)
		i = i + 5
		return m
	elseif b < 254 then
		local m = string.sub(frame.args[1],i,i+5)
		i = i + 6
		return m
	else
		assert(false,"unknown")
		return
	end
end

function p.reverse(frame)
	es = ""
	for v in each_utf8(frame.args[1]) do
		es = v..es
	end
	return es
end
return p