Module:Lustache/Scanner
Documentation for this module may be created at Module:Lustache/Scanner/doc
local string_find, string_match, string_sub =
string.find, string.match, string.sub
local scanner = {}
-- Returns `true` if the tail is empty (end of string).
function scanner:eos()
return self.tail == ""
end
-- Tries to match the given regular expression at the current position.
-- Returns the matched text if it can match, `null` otherwise.
function scanner:scan(pattern)
local match = string_match(self.tail, pattern)
if match and string_find(self.tail, pattern) == 1 then
self.tail = string_sub(self.tail, #match + 1)
self.pos = self.pos + #match
return match
end
end
-- Skips all text until the given regular expression can be matched. Returns
-- the skipped string, which is the entire tail of this scanner if no match
-- can be made.
function scanner:scan_until(pattern)
local match
local pos = string_find(self.tail, pattern)
if pos == nil then
match = self.tail
self.pos = self.pos + #self.tail
self.tail = ""
elseif pos == 1 then
match = nil
else
match = string_sub(self.tail, 1, pos - 1)
self.tail = string_sub(self.tail, pos)
self.pos = self.pos + #match
end
return match
end
function scanner:new(str)
local out = {
str = str,
tail = str,
pos = 1
}
return setmetatable(out, { __index = self } )
end
return scanner