[Computercraft] fPath API

local function path_goback(path,amm)
    pathtbl={}
    s=""
    pathsize=0
    -- Divide string and count the number of
    -- divisions.
     for str in string.gmatch(path, "([^/]+)") do
         pathtbl[#pathtbl+1] = str
     end
     for k, v in pairs(pathtbl) do
         pathsize=k
     end
     pathsize = pathsize - amm
    -- Split string into words based on seperator.
    pathtbl={}
    for str in string.gmatch(path, "([^/]+)") do
        pathtbl[#pathtbl+1] = str
    end
    -- Based on how large the user wants the string to be
    -- add only the string bits that led up to the user defined
    -- size.
    for k, v in pairs(pathtbl) do
        if(k <= pathsize)then s = s..pathtbl[k].."/" end
    end
    return "/" .. s
end
local function path_getsize(path)
    pathtbl={}
    pathsize=0
    -- Divide string and count the number of
    -- divisions.
     for str in string.gmatch(path, "([^/]+)") do
         pathtbl[#pathtbl+1] = str
     end
     for k, v in pairs(pathtbl) do
         pathsize=k
     end
     return pathsize
end

function newpath(name,stuckindex)
    if(name == nil or type(name) ~= "string")then error("PathAPI: Name must be provided for new paths. ") end
    if(string.sub(name,#name,#name) ~= "/")then
        name = name .. "/"
    end
    if(type(stuckindex) ~= "number")then stuckindex = 0 end
    local pathobj = {
        path = name,
        stuckind = stuckindex,
        getsize = function(self)
           return path_getsize(self.path)
        end,
        goback = function(self,amm)
            if(self:getsize() - amm >= self.stuckind)then
               self.path = path_goback(self.path,amm)
               return self.path
            else
                return false
            end
        end,
        getraw = function(self)
            return self.path
        end,
        add = function(self,new)
            self.path = self.path .. new .. "/"
            return self.path
        end,
        set = function(self,npath)
            self.path = npath
            return self.path
        end,
        lockpath = function(self)
            self.stuckind = self:getsize()
        end,
        unlockpath = function(self)
            self.stuckind = 0
        end,
    }
    return pathobj
end