Add support for normalizers in question API.

[weitzman]

This PR is used by drush-ops/drush#2802.

In general, the question API we offer for generators (a long array) might be getting unweildy. Perhaps we should expect (wrapped?) Symfony Question objects. That can be a future PR.

[Chi-teck]

I agree the question array is unwieldy even without nomalizers. I shall deliberate on turning it into object.

[Chi-teck]

Here is an experiment with wrapped Symfony question object.
https://github.com/Chi-teck/drupal-code-generator/tree/generator-question

That can accept questions as follows:

$questions['name'] = new Question('Name', 'Example');

[weitzman]

Excellent.

[Chi-teck]

Merged generator-question into master.

Array syntax for questions is still supported but limited to two values.

$questions['name'] = ['Name', 'Example'];

For setting other properties object syntax is required.

$questions['name'] = new Question('Name', 'Example');
$questions['name']->setValidator($validator);
$questions['name']->setAutocompleterValues($suggestions);
$questions['name']->setNormalizer($normalizer);

Closing the PR as it has become outdated.
Thanks.