Add new configuration option types

[Emmanuel Blot]

Although the following option types are not required by Trac core itself, they might be interesting for various plugins and could be part of Trac core, rather than being implemented in several plugin:

• Choice among a list of option
• Float option

The following add-on could be part of trunk/trac/config.py​

class FloatOption(Option):
    """Descriptor for float configuration options."""
    
    def accessor(self, section, name, default=''):
        """Return the value of the specified option as float.
        
        If the specified option can not be converted to a float, a
        `ConfigurationError` exception is raised.
        
        Valid default input is a string or a float. Returns an float.
        """
        value = section.get(name, default)
        if not value:
            return 0.0
        try:
            return float(value)
        except ValueError:
            raise ConfigurationError('expected real number, got %s' % \
                                     repr(value))

class ChoiceOption(Option):
    """Descriptor for choice configuration options."""

    def __init__(self, section, name, default=None, choices='', doc=''):
        Option.__init__(self, section, name, default, doc)
        self.choices = filter(None, [c.strip() for c in choices.split(',')])

    def accessor(self, section, name, default):
        value = section.get(name, default)
        if value not in self.choices:
            raise ConfigurationError('expected a choice among "%s", got %s' % \
                                     (', '.join(self.choices), repr(value)))
        return value

[Remy Blank]

Sounds useful, but I would tend to wait for at least one use case before integrating this.

[Emmanuel Blot]

Replying to rblank:

Sounds useful, but I would tend to wait for at least one use case before integrating this.

One use case in Trac, or one use case in a plugin ?

[Remy Blank]

Replying to eblot:

One use case in Trac, or one use case in a plugin ?

I meant one use case in a plugin, but since you're asking, I suppose you have one already ;-)

Feel free to re-schedule to an earlier milestone in this case.

[Remy Blank]

FloatOption would be useful for specifying [trac] auto_preview_timeout, as mentioned in comment:4:ticket:9144.

[Remy Blank]

FloatOption was added in [9364].

[Remy Blank]

And ChoiceOption in [9365].

[Martin Scharrer <martin@…>]

In addition to ChoiceOption an option type for multiple non-exclusive options would be useful, e.g. called 'NonexclChoiceOption' (please find a better name :-) ).

In other words: ChoiceOption is like a HTML radio button list where only one element can be selected. The new option NonexclChoiceOption type would be like a HTML check box list where multiple elements can be enabled/disabled.

Graphical configuration tools should render this options as the above HTML form lists.

The Option should return a list of enabled elements/options, so that a plugin could be coded like:

class MyPlugin (component):
   implements ( something )
   
   enabled_features = NonexclChoiceOption('myplugin', 'features', ['feature_a','feature_b','feature_c'], doc='...')
   enabled_realms   = NonexclChoiceOption('myplugin', 'realms', ['wiki','ticket'], doc='Work with wikis and/or tickets')

   def somemethod(self):
      if 'wiki' in self.enabled_realms:
          wiki_code()

      if 'ticket' in self.enabled_realms:
          ticket_code()

      if 'feature_a' in self.enabled_features:
          feature_a_code()   enabled_features = NonexclChoiceOption('myplugin', 'features', default=['A','B','C'], doc='...')

While this can be also done with the ListOption it wouldn't be clear to the user which elements are valid in the list, which is probably the reason ChoiceOption was created.