Re: gtkdialog – variables

[Johnny Rosenberg]

2013/4/17 Johnny Rosenberg <gurus.knugum at gmail.com>:
> I'm experimenting a bit (at level ”beginner”) with gtkdialog and there
> is one thing that I can't figure out.
>
> I can use variables in dialogues, but I can't use those variables
> ”outside” the dialogue in my script.
>
> Here's an example, in which the user pick a car and a colour. Of
> course I want to set two variables with the user's choice.
>
> First create two text files, one of them with car brands and the other
> one with colours:
> Cars:
> Citroën
> Mazda
> Škoda
> Volvo
>
> Colours:
> Black
> Brown
> Red
> Orange
> Yellow
> Green
> Blue
> Violette
> Gray
> White
>
> Now the script:
> #!/bin/bash
> export MainDialog='
>     <vbox>
>         <hbox>
>             <text>
>                 <label>Car:</label>
>             </text>
>             <comboboxentry>
>                 <default>Select a bloody car</default>
>                 <variable>SelectedCar</variable>
>                 <input file>Cars</input>
>             <sensitive>true</sensitive>
>             </comboboxentry>
>             <text>
>                 <label>Colour:</label>
>             </text>
>             <comboboxentry>
>                 <default>Are you going to select a colour or what?</default>
>                 <variable>SelectedColour</variable>
>                 <input file>Colours</input>
>             </comboboxentry>
>         </hbox>
>         <hbox>
>             <button ok></button>
>             <button cancel></button>
>         </hbox>
>     </vbox>'
> gtkdialog --program=MainDialog
> # ----------------------------------------------------------------------------------------------
>
> Running this, selecting ”Citroën” and ”Black” and hitting OK gives the
> following output (at standard out):
> SelectedCar="Citroën"
> SelectedColour="Black"
> EXIT="OK"
>
> However, when trying to use those variables in the Bash part of the
> script, they do no longer exist:
> #!/bin/bash
> export MainDialog='
>     <vbox>
>         <hbox>
>             <text>
>                 <label>Car:</label>
>             </text>
>             <comboboxentry>
>                 <default>Select a bloody car</default>
>                 <variable>SelectedCar</variable>
>                 <input file>Cars</input>
>             <sensitive>true</sensitive>
>             </comboboxentry>
>             <text>
>                 <label>Colour:</label>
>             </text>
>             <comboboxentry>
>                 <default>Are you going to select a colour or what?</default>
>                 <variable>SelectedColour</variable>
>                 <input file>Colours</input>
>             </comboboxentry>
>         </hbox>
>         <hbox>
>             <button ok></button>
>             <button cancel></button>
>         </hbox>
>     </vbox>'
> gtkdialog --program=MainDialog
>
> echo "Buy a ${SelectedColour} ${SelectedCar} today."
> echo "Tomorrow it may be illegal."
> # ----------------------------------------------------------------------------------------------
>
> Both of those variables are empty, unfortunately.
>
> I read as much of the documentation as I found about this, and I only
> found this information:
>
> Directives
> Name: variable export="false"      Description: Variable name, not
> exported to shell
>
> Therefore I tried:
> <variable export="true">SelectedCar</variable>
>
> However, with no luck at all.
>
> Any ideas, please?
>
>
> Ubuntu 12.04
> gtkdialog 0.8.3, compiled from source, see
> http://code.google.com/p/gtkdialog/downloads/detail?name=gtkdialog-0.8.3.tar.gz&can=2&q=
> That page also says: ”Added support for <variable
> export="false">VARNAME</variable>”
> That doesn't seem to be necessary, since the variable doesn't seem to
> be exported anyway…
>
>
> Johnny Rosenberg

I just found an example script with variables that actually works:
#! /bin/bash

export DIALOG='
    <vbox>
       <entry>
           <variable>ENTRY</variable>
       </entry>
    <hbox>
        <button ok></button>
        <button cancel></button>
    </hbox>
</vbox>'

I=$IFS; IFS=""
for STATEMENTS in $(gtkdialog --program DIALOG); do
    eval $STATEMENTS
done
IFS=$I

if [ "$EXIT" = "OK" ]; then
    echo "You entered: $ENTRY."
else
    echo "You pressed the Cancel button."
fi

Seems like they use ”eval” to set the variables. That is of course one
way to do it, but should I really need to do that? If so, when is
”<variable export="false">VariableName</variable>” necessary?

Johnny Rosenberg