Changes in the tkdict module.

[bosonie]

Changes:

• Now the TKDict is an abstract class. Subclasses needs only to define "translate_key.
• It can be instantiated only passing a dictionary or nothing.
• Now the behavior is more similar to a normal dictionary, where the keys are translated keys according to the translation rule. In other words, the class has methods items(), keys() that show the translated keys. In addition there are untranslated_keys() and untranslated_items() methods that return the untranslated keys (the last defined).
• I changed the get_last_key to get_untranslated_key, that clarifies more the scope of the method.
• I also added two methods to get a dictionary with translated keys and one with untranslated keys. I think this is necessary because sometimes external functions (like Dict or the context of WorkChains) require a dict type.
• It fixes the issue #47
• The setting and getting behaviors remain the same.

Let me know if this is ok in your opinion, @vdikan and @pfebrer96

[pfebrer]

I changed the get_last_key to get_untranslated_key, that clarifies more the scope of the method.

I think the name get_last_key indicates that you are only going to get the last key that you attempted to set, which might be important to note. get_last_untranslated_key would be the correct name, but it may be to large :)

Is it safe to assume that most of the times you will want the translated dict? Then you could have get_dict = translated_dict or even dict = property(fget=translated_dict) or value = property(fget=translated_dict). I like to get the "hidden value" of an object with obj.value because it's general and I know that it will work accross different objects (I don't have to know the specific attribute name for each object). This is something that bothers me with aiida nodes, but it may be only me hahaha.

[bosonie]

Thanks @pfebrer96, I think get_last_untranslated_key is fine. Also to name dict() the translated_dict() is fine with me. Regarding the fact to make it a property, I was recently told that when you construct a resource, it is suggested to use a method and not a property. Let's see what @vdikan thinks.

[pfebrer]

Also to name dict() the translated_dict() is fine with me. Regarding the fact to make it a property, I was recently told that when you construct a resource, it is suggested to use a method and not a property. Let's see what @vdikan thinks.

If it's a method instead of a property, then get_* is a better name isn't it? Maybe it's just my own opinion. It would also be consistent with aiida dicts.

[vdikan]

In general the code looks good to me, with the behavior that is expected from Dict-like object. I spotted one difference, that TKDict.items() returns list and not a dict_items class instance. But I do not think it matters. When it does, this type can be cast with TKDict.dict().items()

[bosonie]

Thanks @vdikan and @pfebrer96 for the feedback. In the last commit:

• I renamed get_dict() and get_untranslated_dict() the methods that returns the dictionaries.
• I now use comprehension in their implementation.

I had a look on how to return a dict_items, but I couldn't find the way. For the moment I leave it like that, but if you know how to fix it, let me know!!!