--[[
We could spend all evening, over a pint of beer,
discussing whether Lua is a truely Object Oriented
language or not. But no-one can deny its support for
overriding the behaviour of (table) variables in an
OO like manner.

This demonstration file defines a table of
characteristics (called "visit") which you may
think of as being a class, and which includes a
named piece of code (called "new") which sets up
a new table which exhibits these characteristics.

A metatable is then used to allow operations like
+ and print to be applied to each new table from a
shared base of code, thus saying how the operation
that we are redefining works on this particular
table or table type.
]]

-- These lines are samples of how the contents of
-- this file are called.

-- access = visit.new(line)
-- new_ip_addy = access:getip()
-- visitors[new_ip_addy] + access
-- print (v)

visit = visit or {}

visit_meta = visit_meta or {}

function visit.new(line)
        -- Create a web access log table from
        -- and incoming standard format text log line
        local current = {}
        for ip,status in string.gmatch(line,
                        '(%S+).*"%s+(%d%d%d)%s+') do
                current.ip = ip
                current.status = status
                current.counter = 1
                setmetatable(current,visit_meta)
                end
        return current
        end

function visit_meta.getip(current)
        return current.ip
        end

function visit_meta.__add(this,that)
        local current = {}
        -- define the addition of single accesses into
        -- a series a.k.a. a visit
        current.ip = this.ip
        current.counter = this.counter + that.counter
        current.status = this.status .. " " .. that.status
        setmetatable(current,visit_meta)
        return current
        end

function visit_meta.__tostring(this)
        -- What to print out (rather than a memory addy)
        rv = "Visit from ".. this.ip .. ", " ..
                this.counter .. " requests\n" ..
                this.status .. "\n"
        return rv
        end

-- Point requests for other (non standard) methods back
-- at the metatable
visit_meta.__index = visit_meta