Parrot-0.0.1

Phil Hunt philh at vision25.demon.co.uk
Tue Aug 24 03:16:13 CEST 1999


In article <7ps4ma$n06$1 at wagner.wagner.home>
           vitus at wagner.rinet.ru "Victor Wagner" writes:
> Phil Hunt <philh at vision25.demon.co.uk> wrote:
> : Parrot is a text-based GUI builder, written by Philip Hunt. It is 
> : intended to be used by programmers writing GUI applications. To 
> : use Parrot, first you create a *.par file describing your 
> : application's GUI. Your file might look something like this:
> 
> Compare this with code below:
> : -----------Cut here-------------------------------
> : window @MyWindow "My First Window" {
> :    menuBar {
> :       menu "File" { 
> :          menuItem @New "New" 
> :          menuItem @Exit "Exit"
> :       }
> :       menu "Help" { 
> :          menuItem @About "About..."
> :       }
> :    }
> :    colLayout {
> :       rowLayout {
> :          label "First row!"
> :          button @Button1 "Press me"
> :          button @Button2 "And me"
> :       }
> :       rowLayout {
> :          label "Which units:"
> :          radioButton @inchRB "inches"
> :          radioButton @feetRB "feet"
> :          radioButton @yardRB "yards"
> :          radioButton @mileRB "miles"
> :       }
> :    }
> : }
> : -----------Cut here-------------------------------
> 
> 
> toplevel .mywindow -menu .mywindow.m; wm title .mywindow "My First Window"
> menu .mywindow.m
>   .mywindow.m add cascade -label "File" -menu .mywindow.m.file 
>      menu .mywindow.m.file
>         .mywindow.m.file  add command -label New -command new_file
>         .mywindow.m.file add command -label Exit -command exit
>   .mywindow.m add cascade -label "Help" -menu .mywindow.m.help
>      menu .mywindow.m.help
>         .mywindow.m.help add command -label About... -command about
> frame .mywindow.f1
>   label .mywindow.f1.l1 -text "First row"
>   button .mywindow.f1.b1 -text "Press me" -command do_something
>   button .mywindow.f1.b2 -text "And me" -command do_something_else
>   pack .mywindow.f1.l1 .mywindow.f1.b1 .mywindow.f1.b2 -side left -padx 10
>   
> frame .mywindow.f2
>  label .mywindow.f2.l1 -text "Which units:"
>  # Here I got tired of typing and let the program produce rest
>  pack .mywindow.f2.l1 -side left -padx 10
>  foreach unit {inches feet yards miles} {
>     radiobutton .mywindow.f2.$unit -text $unit -value $unit -variable unit
>     pack .mywindow.f2.$unit -side left -padx 10
>  }
> pack .mywindow.f1 .mywindow.f2 -side top -pady 5 -anchor n
> 
> This is tcl/tk. Almost no difference.

If that is what you think, you obviously have a different aesthetic
sense than me.

Don't forget that Parrot will be able to do more than what is in that
simple example. For example:

   sub.fcol=red

would mean ``make all components inside the current component
default to having an attribute ``fcol'' with thew value ``red'' 
(i.e red foreground); these defaults can be overridden by the
attributes in the actual components''

Creating a default attribute for a component-type will also
be possible, e.g:

   all.label.font=Helvetica

> A bit more verbose, but there are
> numerous ways to shorten code, which I haven't used intentionally until
> I got tired and used a loop to produce four radiobuttons.
> 
> And this is not something which should be run through preprocessor.
> This is already runnable code. Just add #!/usr/bin/wish at the beginning
> and chmod +x it. And if you define procedures do_something ,
> do_something_else and new_file, it may even do something useful.
> Oh yes, there is empty default window floating around. I could create
> all the widgets in it directly, but in original code it was obvoisly not
> main window of program, so I choose to create separate toplevel.

Could it write C output that calls the GTK+ library, or C++/Qt,
or other language/GUI-toolkit combinations?
 
> Note also that all this things are done runtime, not when preprocessing,
> so, for instance I could get list of units via database query or
> substitute different lists according to current locale.
> 
> Once again: who need so-called GUI builders while we have scripting
> languages, which provide same level of abstraction, but much more
> flexibilty, becouse interface is created run-time? 
> 
> Really it is very simple to define parrot interpreter on tcl - just
> define commands such as window, columnLayout, rowLayout as tcl procedures 
> which substitute
> something by default.

Would anyone want to do this in Tcl as opposed to Python? (Not
wishing to get into another language war :-)).

> And parrot files would become runnable. But pretty
> useless, becouse I've not seen any way to attach functionality to these
> windows.

Use subclassing.

-- 
Phil Hunt....philh at vision25.demon.co.uk





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