From: Jeppe Jakobsen <jeppe88@...>
Date: 2006-04-14T22:16:49+09:00
Subject: Re: Q about tk buttons

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Thank you that really cleared things up :)

But I don't understand this line though
>entry.bind('Return', proc{button.invoke})

It doesn't seem to make any difference whether I include it in the program
or not. I tried to read about it in the documentation, but I only understoo=
d
that it had something to do with invoking the command of the button.

2006/4/14, Hidetoshi NAGAI <nagai@ai.kyutech.ac.jp>:
>
> Hmmm... There are some problems.
>
> From: "Jeppe Jakobsen" <jeppe88@gmail.com>
> Subject: Re: Q about tk buttons
> Date: Thu, 13 Apr 2006 22:33:18 +0900
> Message-ID: <99b4ad3b0604130633t48adb432n4417c3fd27f3b8f4@mail.gmail.com>
>
> > require "tk"
> > #methods
> > def guess
> >     if (guess.value =3D=3D right_guess.value)
> >         status.value =3D "Correct!"
> >     else
> >         number_of_guess.numeric +=3D 1
> >         status.value =3D "Sorry, no luck"
> >     end
> > end
>
> Probably, you'll want to refer local variables on main.
> But those variables are out of scope in the method.
> If arguments bothers you, you can use a Proc object instead of a method.
>
> Next, please see here.
>
> > def guess
>       ^^^^^
> > guess =3D TkVariable.new()
>   ^^^^^
>
> There is conflict of names.
> So, "proc{guess}" refers the local variable.
> If you want to call "guess" method, you must use "proc{guess()}".
>
> > root =3D Tk.mainloop
>
> Probably, the return value is not useful.
>
> If I were you, I may write such like as the following.
> ----------------------------------------------------
> require 'tk'
>
> right_guess =3D rand(21)
> number_of_guess =3D TkVariable.new(0)
>
> Tk.root.title('Number guess')
>
> TkLabel.new(:textvariable=3D>number_of_guess).pack(:side=3D>:top,
> :pady=3D>10)
>
> status =3D TkLabel.new(:text=3D>"Entry your guess and press the button",
>                      :width=3D>37).pack(:side=3D>:bottom, :pady=3D>10)
>
> entry =3D TkEntry.new.pack(:side=3D>:top, :pady=3D>10)
>
> guess_cmd =3D proc{
>   value =3D entry.value
>   if value.empty? || value.to_i !=3D right_guess
>     number_of_guess.numeric +=3D 1
>     status.text('Sorry, no luck')
>   else
>     status.text('Correct!')
>   end
> }
>
> button =3D TkButton.new(:text=3D>'Guess',
> :command=3D>guess_cmd).pack(:side=3D>:top, :p\ady=3D>10)
>
> entry.bind('Return', proc{button.invoke})
>
> Tk.mainloop
> ----------------------------------------------------
> --
> Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)
>
>


--
"winners never quit, quitters never win"

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