local index_module = "Module:index"
local string_linelen_module = "Module:string/linelen"
local find = string.find
local require = require
local sub = string.sub
local function index_range(...)
index_range = require(index_module).range
return index_range(...)
end
local function linelen(...)
linelen = require(string_linelen_module)
return linelen(...)
end
return function(str, i, j)
i, j = index_range(str, i, j, linelen)
if j and j < i then
return ""
end
local first, pos1, pos2, newline, pattern, plain = 1
if not find(str, "\r", nil, true) then
pattern, plain = "\n", true
elseif not find(str, "\n", nil, true) then
pattern, plain = "\r", true
else
pattern = "([\n\r]\n?)"
end
for _ = 1, i - 1 do
pos1, pos2, newline = find(str, pattern, first, plain)
if pos1 == nil then
return ""
end
first = newline == "\n\n" and pos2 or pos2 + 1
end
if j == nil then
return sub(str, first)
end
local last = first
for _ = i, j do
pos1, pos2, newline = find(str, pattern, last, plain)
if pos1 == nil then
return sub(str, first)
end
last = newline == "\n\n" and pos2 or pos2 + 1
end
last = pos1 - 1
return sub(str, first, last)
end
