Help me pick an API design (OO vs functional)

[Michael Herrmann]

On Tuesday, March 26, 2013 11:26:30 AM UTC+1, Dave Angel wrote:
> ...
> Seems to me that the official interface should all be methods.  However, 
> you could have a new object which always represents the "focus" window. 
>   Then the USER could define trivial functions:
> 
> def write(*args):
>      focused.write(*args)

It's an interesting idea. But why not give this write(...) to them in the first place? Am I the only one who appreciates the simplicity of

        start("Notepad") 
        write("Hello World!") 
        press(CTRL + 's') 
        write("test.txt", into="File name") 
        click("Save") 
        press(ALT + F4) 

over 

        notepad = start("Notepad") 
        notepad.write("Hello World!") 
        notepad.press(CTRL + 's') 
        notepad.write("test.txt", into="File name") 
        notepad.click("Save") 
        notepad.press(ALT + F4)?

> Somewhere in this thread you mention that save() creates a new window, 
> so a method-oriented approach would require that the user get that 
> window object, and call its methods rather than the original window's. 
> I say that's a very good thing, since the things you send may very well 
> have very different meanings to the save dialog than they do in the 
> original one.

save() is not a function, but I assume you mean the action that opens the "Save" dialogue (I think that'd be `press(CTRL + 's')`). You are right that it's nice for it to be explicit. However, in 95% of cases, the window you want the next action to be performed in is the window that is currently active. I appreciate the explicitness, but to force it on the user for only 5% of cases seems a bit much. 

> Another concern I'd have is what happens if the user changes focus with 
> his mouse?  Does that change the meaning you had for focus() in the 
> above exchange?  Do you want your press() method to apply to a different 
> window when the user changes to that window?

No. Internally, we remember which window is the currently active window. If you just run a script without user-intervention, this will be the respective foreground window. If some other window is in the foreground - which most typically happens when the user is interactively entering commands one after the other, so the foreground window is the console window, we do switch to the window that's supposed to be the active one. It may sound like black magic, but it works very well in practice, and really is not too ambiguous. When you read a script like

	start("Notepad")
	write("Hello World")
	press(CTRL + 's')
	write("test.txt", into="File name")
	click("Save")
	click("Close")

I hold that you intuitively know what's going on, without even thinking about window switching.

Best,
Michael
www.getautoma.com