Deprecate input()

[Bengt Richter]

On 15 Apr 2002 13:58:11 -0500, Ian Bicking <ianb at colorstudy.com> wrote:

>On Mon, 2002-04-15 at 06:35, Magnus Lie Hetland wrote:
>> But (in the (very?) long run) I think that the name "input" should
>> then be used for what is now raw_input. I know -- breakage, and all
>> that... I just think it fairly odd to have *only* raw_input, since the
>> "raw" qualification then becomes fairly meaningless.
>
>Why not just make input into what it should be, a moderately-evaluating
>raw_input... like:
>
>def input(prompt=''):
>    val = raw_input(prompt)
>    for converter in [int, float, complex]:
>        try:
>            return converter(val)
>        except ValueError:
>            pass
>    return val
>
>
>Of course, it gets more complex if you allow lists, dictionaries, and
>tuples... which you probably should.  But that's certainly doable while
>still being safe.
>

You could also just add a sequence of validation conditions, e.g., (pseudocode, not tested):

    def prompted_input(prompt='', *validation_seq):
        val = [raw_input(prompt)]
        for valcond in validation_seq:
            valcond[0](val, valcond[1:]) #raises exception if cond violated
        return val[0]

to be called something like (example shows more than usual checks ;-):

        prompted_input(
            'Enter a number: ',
            (vfun_conv, [int], 'Error: %(theValue) is not an integer.'),
            (vfun_min, 3, 'Need at least %(theMin)'),
            (vfun_max, 8, 'Must be no more than %(theMax)'),
            (vfun_sel, (3,7), 'Must select from %(theSet)'),
            (mySpecialCheck, myArgs)
            )

with vfun_xxx being builtin standard validation functions, but the list not
limited to those. Custom error text would be passed through via ValidationCheck exception.
Using [val] vs val allows possibility of repairing/modifying something in mySpecialCheck.

Regards,
Bengt Richter