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Re: Initialization cell and button

• To: mathgroup at smc.vnet.net
• Subject: [mg70107] Re: Initialization cell and button
• From: Markus Huber <mhla at gmx.at>
• Date: Wed, 4 Oct 2006 05:58:44 -0400 (EDT)
• References: <eftdnh$6co$1@smc.vnet.net>

Thank you, the version with the InterpretationBox will work fine for me.

Regards,
Markus

Ingolf Dahl wrote:
> Markus,
> You must remember that the FrontEnd is almost, but not exactly, as smart as
> the bomb in the computer game "Starship Titanic" by Douglas Adams... When
> the "EvaluateInitialization" command is executed, the initialization cells
> are not inserted into the program flow and evaluated immediately; they just
> are put onto the evaluation stack, to be evaluated after the button function
> as such. You thus must put the print command even later on the evaluation
> stack to obtain the desired functionality. The easiest way is of course to
> include a print command as the last initialization cell, but that solution
> is probably too simple for your purposes (?). Another solution is to hide a
> print command inside the button cell. Execute the following command to
> obtain such a button:
> 
> 
> NotebookWrite[InputNotebook[], Cell[BoxData[InterpretationBox[ButtonBox["a",
> ButtonFunction:>
> FrontEndExecute[CompoundExpression[FrontEndToken["EvaluateInitialization"],
> SelectionMove[ButtonNotebook[],All,ButtonCell],
> FrontEndToken["EvaluateCells"]]], ButtonEvaluator->None, Active->True,
> ButtonFrame->"DialogBox"], Print@a]],"Input"]]
> 
> (You have to modify the button if you want to generate a palette from it.) 
> 
> Another approach to put commands onto the evaluation stack is to let the
> ButtonFunction create a scrap notebook, write the commands there together
> with a command that closes the same scrap notebook, and then use
> SelectionEvaluate to evaluate these commands. But in this case we then would
> have to redirect the output of Print to be able to see anything.
> 
> Best regards
> 
> Ingolf Dahl
> 
> 
> 
>> -----Original Message-----
>> From: Markus Huber [mailto:mhla at gmx.at] 
To: mathgroup at smc.vnet.net
>> Subject: [mg70107]  Initialization cell and button
>>
>>
>> I've got the following simplified problem with a button:
>>
>> Create an initialization cell which contains a=1;
>>
>> Create a button with
>>
>> Button["a", Active -> True,
>>      ButtonFunction :> (FrontEndExecute[
>>            FrontEndToken["EvaluateInitialization"]];
>>          Print@a), ButtonEvaluator -> Automatic] // DisplayForm
>>
>> but say no, if Mathematica asks if to evaluate the 
>> initialization cells in the NB.
>>
>> Now press the button .
>>
>> In my opinion the result should be the printout of 1. Instead 
>> M prints a. If you press the button again it prints correctly 1.
>>
>> Why is M not aware of the value of a when evaluating the 
>> Print function although the initialization cells should have 
>> been evaluated already?
>>
>>
>> Regards,
>> Markus Huber
>>
> 
>