Hi Rici,
Thanks for the reply!
See my comments below.
2006/12/1, Rici Lake <lua@ricilake.net>:
On 1-Dec-06, at 12:31 AM, wang xu wrote:
> Is there a generic way to automatically update one
variable when the
> value of another variable is changed?
No. (And why do you want to do that?)
I have a View, the view is a Text Widget, which has an
attribute "str", when
the str is modified, the Text widget will update the
Screen with the string.
I also have a Model, which is a table containing many
strings, each string
is corresponding to one Text Widget.
What I want to do by a linked variable are:
1) when a string in the model changes, the str in the
view update
automatically.
2) when the str in the Text Widget changes(by the user
through GUI), the
sting in the Model table update automatically too.
The closest you can do is to implement your own "boxed"
values, using
tables with a single key (say, 1):
val1 = {"a"}
val2 = val1
val1[1] = "b"
=val2[1]
You could dress it up in O-O notation:
do
local meta = {}
meta.__index = meta
function meta:set(v) self[1] = v end
function meta:get() return self[1] end
function Box(v)
return setmetatable({v}, meta)
end
end
val1 = Box("a")
val2 = val1
=val2:get()
val1:set("b")
=val2:get()
Yeah. that's a way. but I need to change my model and
widget
implementation...
I came from the TCL world, and there is a tracevar can
do this, so I'm
wondering if Lua has similar functionality..
