Avoiding a SyntaxError when giving no input

[Skip Montanaro]

    Heiko> I got a python script here that takes strings with the input() -
    Heiko> function.  Now, if I dont enter anything, and just press enter,
    Heiko> python exits with a SyntaxError.  How can I force python to just
    Heiko> ask again for a value?  I tried it with exception handling, but
    Heiko> that doesnt seem to work with SyntaxError.

You may not want to call input() directly.  It is, in effect:

    def input(prompt):
        return eval(raw_input(prompt))

Instead, you might want to use raw_input and check responses before calling
eval:

    while 1:
        ans = raw_input(prompt)
        if not validate_input(ans):
            print "invalid input:", repr(ans)
        else:
            result = eval(ans)
            break

The validate_input function would catch empty strings, dangerous stuff,
etc.  You might want to call eval() with explicit globals and locals args as
well to minimize potential for damaging input.

-- 
Skip Montanaro (skip at pobox.com - http://www.mojam.com/)