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When my daughter asked me help with her spelling homework, for me the obvious thing to do was to write a Mathematica program for it.

The words:

words = {"lightning", "thunder", "cloudy"};

The code:

Grid[ Module[{x = 0, t = 0}, { #, Button["Start", t = Hold@AbsoluteTime[] - AbsoluteTime[]], Button[Style["\[Checkmark]", Darker@Green], t = ReleaseHold[t]; x++], Button[Style[ "\[Times]", Red ], t = ReleaseHold[t]; x--], Dynamic[x], Dynamic[Clock[]; ReleaseHold[t]] } ] & /@ words]

Which produces this output:

screenshot

So when I ask her a word, I click "start". Then I click ✔ or × if her answer is right or wrong respectively. I plan to keep track of time to answer, so the timer now shows how much time it took to answer.

So my question is: Why do I have to use Module instead of DynamicModule? For some reason the Grid command does not work if I use DynamicModule. On the other hand, if I use Module (as it is shown), then the syntax highlighter shows my "t" and "x" variables in red as if I am doing something wrong: enter image description here

Update: I have just realized that using Module instead of DynamicModule is not a viable option as the scores are lost when you reopen the notebook.

Update 2: For the record, this is the finished program incorporating the advice from Mr.Wizard and kguler

DynamicModule[{x, t, status, h}, x[_] = 0; t[_] = 0; status[_] = False; h[_] = {}; Column[{Grid[ MapIndexed[{ #, Button["Start", Speak@#; status[#2] = True; t[#2] = Hold@AbsoluteTime[] -AbsoluteTime[], Enabled -> Dynamic[! status[#2]]], Button[Style["\[Checkmark]", Darker@Green], t[#2] = ReleaseHold[t[#2]]; x[#2]++; AppendTo[h[#2], t[#2]]; status[#2] = False, Enabled -> Dynamic[status[#2]]], Button[Style["\[Times]", Red], t[#2] = ReleaseHold[t[#2]]; x[#2]--; AppendTo[h[#2], -t[#2]]; status[#2] = False, Enabled -> Dynamic[status[#2]]], Button["spell", Speak@StringJoin[Riffle[Characters[#], ","]]], Dynamic[x[#2]], Dynamic[Clock[]; ReleaseHold[NumberForm[t[#2], 2]]], Dynamic@ If[Length@h[#2] > 0, Module[{z = Transpose[{Abs[#], Sign[#]} & /@ h[#2]]}, Graphics[ (Rectangle @@@ (Partition[{Accumulate[First@z],Last@z}\[Transpose],2,1,{2,2},{{0, 0}}] /. {{x1_, y1_Integer}, {x2_, y2_Integer}} -> {{x1 + 0.2, 0}, {x2, y2}})) /. {Rectangle[{x1_,0}, {x2_, 1}] -> {Darker@Green, Rectangle[{x1, 0}, {x2, 1}]}, Rectangle[{x1_,0}, {x2_,-1}] -> {Red, Rectangle[{x1,0}, {x2, -1}]}}, ImageSize -> {Automatic, 20}, PlotRange -> {-1, 1}]], "" ] } &, words], Alignment -> Left], Row[{Button[ "reset", (x[{#}] = 0; t[{#}] = 0; h[{#}] = {}) & /@ Range@Length@words], Spacer[10]}]}]]

enter image description here

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    $\begingroup$ You should really look at Anki (which of course doesn't mean that we shouldn't solve this in Mathematica!) $\endgroup$ Commented Feb 16, 2012 at 13:16
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    $\begingroup$ +1. Using Beep is perhaps going too far, but ... Speak and Characters might come handy in this task: Speak["potatoes"] and StringJoin[Riffle[Characters["potatoes"], " "]]. $\endgroup$ Commented Feb 16, 2012 at 18:36
  • $\begingroup$ I happened to glance at this again and I noticed that you did not localize pattern names with RuleDelayed. For example Rectangle[{x1_,0}, {x2_,-1}] -> {Red, Rectangle[{x1,0}, {x2, -1}] should be written Rectangle[{x1_,0}, {x2_,-1}] :> {Red, Rectangle[{x1,0}, {x2, -1}] to protect x1 and x2. $\endgroup$ Commented Feb 14, 2013 at 19:52

1 Answer 1

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This is because the object created by DynamicModule does not actually evaluate until it is displayed, therefore Grid has nothing to format other than the outer list.

words = {"lightning", "lightning", "cloudy"}; dynlist = DynamicModule[{x = 0, t = 0}, { #, Button["Start", t = Hold@AbsoluteTime[] - AbsoluteTime[]], Button[Style["\[Checkmark]", Darker@Green], t = ReleaseHold[t]; x++], Button[Style[ "\[Times]", Red ], t = ReleaseHold[t]; x--], Dynamic[x], Dynamic[Clock[]; ReleaseHold[t]] } ] & /@ words; ToString[ dynlist[[1]] ]

"DynamicModule[{x = 0, t = 0}, {lightning, Button[Start, t = \ Hold[AbsoluteTime[]] - AbsoluteTime[]], Button[[Checkmark], t = \ ReleaseHold[t]; x++], Button[[Times], t = ReleaseHold[t]; x--], \ Dynamic[x], Dynamic[Clock[]; ReleaseHold[t]]}, DynamicModuleValues :> \ {}]"

You could build the rows inside the module:

Column[ DynamicModule[{x = 0, t = 0}, Grid@{{ #, Button["Start", t = Hold@AbsoluteTime[] - AbsoluteTime[]], Button[Style["\[Checkmark]", Darker@Green], t = ReleaseHold[t]; x++], Button[Style[ "\[Times]", Red ], t = ReleaseHold[t]; x--], Dynamic[x], Dynamic[Clock[]; ReleaseHold[t]] }} ] & /@ words]

Mathematica graphics

Addressing your comment you could move the map operation inside Grid like this:

DynamicModule[{x, t}, x[_] = 0; t[_] = 0; Grid[ MapIndexed[ {#, Button["Start", t[#2] = Hold@AbsoluteTime[] - AbsoluteTime[]], Button[Style["\[Checkmark]", Darker@Green], t[#2] = ReleaseHold[t[#2]]; x[#2]++], Button[Style["\[Times]", Red], t[#2] = ReleaseHold[t[#2]]; x[#2]--], Dynamic[x[#2]], Dynamic[Clock[]; ReleaseHold[t[#2]]]} &, words ]]]

Mathematica graphics

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  • $\begingroup$ Yes, but it needs to be on a grid. Otherwise it looks ugly as you have shown. $\endgroup$ Commented Feb 16, 2012 at 15:49
  • $\begingroup$ @Gustavo see edit; sorry for sloppy formatting but I don't have time to make it pretty. $\endgroup$ Commented Feb 16, 2012 at 16:41
  • $\begingroup$ Thank you! I had tried unsuccessfully with Map, but I see you cleverly solved it using MapIndexed. $\endgroup$ Commented Feb 16, 2012 at 17:00

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