lsyncd/mantle/array.lua
2018-03-15 13:43:02 +01:00

169 lines
2.3 KiB
Lua

--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- array.lua
--
--
-- Array tables error if accessed with a non-number.
-- They maintain their length as an attribute and are zero based.
--
--
-- This code assumes your editor is at least 100 chars wide.
--
-- License: GPLv2 (see COPYING) or any later version
-- Authors: Axel Kittenberger <axkibe@gmail.com>
--
--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
if lsyncd_version
then
print( 'Error, Lsyncd mantle already loaded' )
os.exit( -1 )
end
--
-- Metatable.
--
local mt = { }
--
-- Key to native table.
--
local k_nt = { }
--
-- Key to size entry.
--
local k_size = { }
--
-- On accessing a nil index.
--
mt.__index = function
(
self,
k -- key used to access
)
if type( k ) ~= 'number'
then
error( 'Array, key "'..k..'" invalid', 2 )
end
if k < 0 or k >= self[ k_size ]
then
error( 'Array, key "'..k..'" out of bonds', 2 )
end
return self[ k_nt ][ k ]
end
--
-- On assigning a new index.
--
mt.__newindex = function
(
self,
k, -- key value to assign to
v -- value to assign
)
if type( k ) ~= 'number'
then
error( 'Array, key "'..k..'" invalid', 2 )
end
if k < 0 or k > self[ k_size ]
then
error( 'Array, key "'..k..'" out of bonds', 2 )
end
if k == self[ k_size ]
then
self[ k_size ] = self[ k_size ] + 1
end
self[ k_nt ][ k ] = v
end
--
-- Returns the length of the array.
--
mt.__len = function
(
self
)
return self[ k_size ]
end
--
-- Errors on use of pairs( )
--
mt.__pairs = function
(
self
)
error( 'Array, do not use pairs( )', 2 )
end
--
-- Returns next value in iterator.
--
local function iter
(
self,
pos
)
pos = pos + 1
if pos == self[ k_size ] then return nil end
return pos, self[ k_nt ][ pos ]
end
--
-- Allows walking throw the array.
--
mt.__ipairs = function
(
self
)
return iter, self, -1
end
--
-- Pushes a new new value on the end of the array
--
local function push
(
self,
v
)
self[ k_nt ][ self[ k_size ] ] = v
self[ k_size ] = self[ k_size ] + 1
end
--
-- Creates a new array.
--
local function new
( )
-- k_nt is a native table, private to this object.
local o =
{
push = push,
[ k_size ] = 0,
[ k_nt ] = { }
}
setmetatable( o, mt )
return o
end
--
-- Exported interface.
--
Array = { new = new }