80 lines
1.8 KiB
Lua
80 lines
1.8 KiB
Lua
--- Tables as trees.
|
|
module ("tree", package.seeall)
|
|
|
|
require "list"
|
|
|
|
|
|
local metatable = {}
|
|
--- Make a table into a tree
|
|
-- @param t table
|
|
-- @return tree
|
|
function new (t)
|
|
return setmetatable (t or {}, metatable)
|
|
end
|
|
|
|
--- Tree <code>__index</code> metamethod.
|
|
-- @param tr tree
|
|
-- @param i non-table, or list of indices <code>{i<sub>1</sub> ...
|
|
-- i<sub>n</sub>}</code>
|
|
-- @return <code>tr[i]...[i<sub>n</sub>]</code> if i is a table, or
|
|
-- <code>tr[i]</code> otherwise
|
|
function metatable.__index (tr, i)
|
|
if type (i) == "table" then
|
|
return list.foldl (op["[]"], tr, i)
|
|
else
|
|
return rawget (tr, i)
|
|
end
|
|
end
|
|
|
|
--- Tree <code>__newindex</code> metamethod.
|
|
-- Sets <code>tr[i<sub>1</sub>]...[i<sub>n</sub>] = v</code> if i is a
|
|
-- table, or <code>tr[i] = v</code> otherwise
|
|
-- @param tr tree
|
|
-- @param i non-table, or list of indices <code>{i<sub>1</sub> ...
|
|
-- i<sub>n</sub>}</code>
|
|
-- @param v value
|
|
function metatable.__newindex (tr, i, v)
|
|
if type (i) == "table" then
|
|
for n = 1, #i - 1 do
|
|
if type (tr[i[n]]) ~= "table" then
|
|
tr[i[n]] = tree.new ()
|
|
end
|
|
tr = tr[i[n]]
|
|
end
|
|
rawset (tr, i[#i], v)
|
|
else
|
|
rawset (tr, i, v)
|
|
end
|
|
end
|
|
|
|
--- Make a deep copy of a tree, including any metatables
|
|
-- @param t table
|
|
-- @param nometa if non-nil don't copy metatables
|
|
-- @return copy of table
|
|
function clone (t, nometa)
|
|
local r = {}
|
|
if not nometa then
|
|
setmetatable (r, getmetatable (t))
|
|
end
|
|
local d = {[t] = r}
|
|
local function copy (o, x)
|
|
for i, v in pairs (x) do
|
|
if type (v) == "table" then
|
|
if not d[v] then
|
|
d[v] = {}
|
|
if not nometa then
|
|
setmetatable (d[v], getmetatable (v))
|
|
end
|
|
o[i] = copy (d[v], v)
|
|
else
|
|
o[i] = d[v]
|
|
end
|
|
else
|
|
o[i] = v
|
|
end
|
|
end
|
|
return o
|
|
end
|
|
return copy (r, t)
|
|
end
|