[Tutor] __doc__ strings for attributes?

[Wesley Brooks]

Thanks for the comments.

>shape0 = BasicShape()
>shape1 = BasicShape('cylinder', [20.,10.,36.])

I like this way of doing things, I could inherit the 3D data object's
class and get it to build on itself. I could for example use a
function definition like the following:

def __init__(*args, **paramDict):
    self.args = args
    self.xScanSpacing = paramDict['xScanSpacing']
    etc.

and I get a very flexible base to expand on. I do however get a real
problem when it comes to documenting the expected keywords and running
into huge doc strings, when I prefer concise documentation.

I like the following:

class a:
    def __init__(*args, **paramDict):
        expectedParam = ['xScanSpacing', 'yScanSpacing'....]
        paramDocDict = {'xScanSpacing': 'float mm spacing for x axis
hatches', ...}

To find out what parameters this object works with I could do;

>>> aa = a()
>>> aa.expectedParam
['xScanSpacing', 'yScanSpacing'....]
>>> aa.paramDocDict['xScanSpacing']
'float mm spacing for x axis hatches'

Is there an standard way of doing this?

This isn't as nice to use as the doc strings and dir function. For
example if I wanted to find out what I can do with a string I could
call dir(' ') on the interpreter and have a list of functions and
attributes contained in the string object. If I wanted a quick
explanation of one function I could run;

>>> print ' '.strip.__doc__
S.strip([chars]) -> string or unicode

Return a copy of the string S with leading and trailing
whitespace removed.
If chars is given and not None, remove characters in chars instead.
If chars is unicode, S will be converted to unicode before stripping
>>>

Cheers,

Wesley Brooks.

On 09/11/2007, Evert Rol <evert.rol at gmail.com> wrote:
> > How can I add information to an object to explain what it expects as
> > it's attributes? For instance I may have an object that creates a CAD
> > file based on a set of default values which are set by the __init__
> > but can be altered before it runs. for example;
>
> Why don't you specify a doc-string in your class declaration?
>
> class MakeBasicShape:
>      """basic information
>
>      detailed information about attributes
>      """
>
>
> But, with what you do, why don't you add parameters to MakeIt()?
>
>      def MakeIt(self, shape='cuboid', bounds=[0.,10.,0.,10.,0.,10.]):
>          self.boundsInfo = [shape, bounds]
>
>
> Or perhaps, let your class be the object you're creating (and rename
> it to 'BasicShape'; verbs in class names seem a bit odd to me)? The
> __init__ method would then fulfill the function of the MakeIt method,
> and things would become:
> shape0 = BasicShape()
> shape1 = BasicShape('cylinder', [20.,10.,36.])
> etc.
>
> That is, unless you're doing other things in your factory object that
> don't show up here.
>
>
> >     def MakeIt(self):
> >         assert self.boundsInfo[0] in self.boundsOptions,
> >                "Option not recognised: %s", self.boundsInfo[0]
>
> I also wouldn't use assert, but try: except:  in MakeIt() for example
> (assert is really for debugging, but here it looks more like you're
> trying to prevent user mistakes).
>
>
> Anyway, hope that that gets you further.
>
>    Evert
>
>
> >         if self.boundsInfo[0] == 'cuboid'
> >             bounds = self.boundsInfo[1]
> >             .... # code to make box
> >         elif self.boundsInfo[0] == 'cylinder'
> >             [height, radius, noSides] = self.boundsInfo[1]
> >             .... # code to make cylinder
> >         elif self.boundsInfo[0] == 'cad'
> >             fileName = self.boundsInfo[1]
> >             .... # code to load CAD file
> >         return shape
> >
> >
> > if __name__ == '__main__':
> >     shapeFactory0 = MakeBasicShape()
> >     shape0 = shapeFactory.MakeIt() # a box
> >
> >     shapeFactory1 = MakeBasicShape()
> >     shapeFactory1.boundsInfo = ['cylinder' ,[20.,10.,36]]
> >     shape1 = shapeFactory.MakeIt() # a cylinder
> >
> >     shapeFactory2 = MakeBasicShape()
> >     shapeFactory2.boundsInfo = ['cad' ,'/home/Wes/BigHand.stl']
> >     shape2 = shapeFactory.MakeIt() # a CAD file
> >
> > While this example could be coded with different functions for making
> > a box, cylinder, and loading the CAD file I wanted to use attributes
> > to control the object to simplify interaction with it from the user
> > interface code. I would like to move away from getters and setters as
> > they're taking up vast chunks of my code at the moment and do very
> > little!
> >
> > Can I also stop new attributes being added to the MakeBasicShape
> > class?
> >
> > Thanks in advance of any help.
> >
> > Wesley Brooks
> >
>