Any idea how to get this to work?
y = {}; Table[Button[x, AppendTo[y, Evaluate[x]]], {x, 5}] Result: Click [1] , click [2], get {6,6}
I'm trivializing the actual task, but the goal is to set what a button does inside a Map or a Table or ParallelTable.
Please Help!
EDIT
Figured it out... Evaluate works at first level only. Here, it's too deep. So I used ReplaceRule:
Remove[sub]; y = {}; Table[Button[x, AppendTo[y, sub]] /. sub -> x, {x, 5}] This is a job for With. With is used to insert an evaluated expression into another expression at any depth -- even into parts of the expression that are not evaluated right away like the second argument to Button:
y = {}; Table[With[{x = i}, Button[x, AppendTo[y, x]]], {i, 5}] In simple cases like this, some people (myself included) prefer to use the same symbol (x in this case) for both the With and Table variables, thus:
y = {}; Table[With[{x = x}, Button[x, AppendTo[y, x]]], {x, 5}] 
With[...], forces it to inject unevaluated expression(s) into its body. I mention it here because I thought you might find it interesting.
Replacement rules and pure functions offer concise alternatives to With. For example:
y={}; Range[5] /. x_Integer :> Button[x, AppendTo[y, x]] or
y = {}; Replace[Range[5], x_ :> Button[x, AppendTo[y, x]], {1}] or
y = {}; Array[Button[#, AppendTo[y, #]] &, {5}] or
y = {}; Button[#, AppendTo[y, #]] & /@ Range[5] For another example comparing these techniques, see my post here, where they are applied to a problem of creating a list of pure functions with parameter embedded in their body (closures).
Evaluate works at first level only. Here, it's too deep. So I used ReplaceRule:
Remove[sub]; y = {}; Table[ Button[x, AppendTo[y, sub]] /. sub -> x, {x, 5}] 
Remove[sub]; y = {}; Table[ Button[x, AppendTo[y, sub]] /. sub -> x, {x, 5}]as an answer