Add more useful help for special name in `help()`

[Locked-chess-official]

Feature or enhancement

Proposal:

Now, use help("__name__") and some other special variables' names will still get the help from their class. I think that we can add the useful help on them. For example:

>>>help("__name__")
1. module.__name__ : if the module is run as the main module, the value is ‘_main_‘, or the name is the filename of the module. For example:if __name__ == "__main__": ...can control which code don’t run when the module is imported.

2. cls.__name__: the name of the class. It must be str.

For other special variables (such as __file__), we can alse print the similar detailed help. And I think that the sentences need to be friendly.

Also welcome to give the ideals on new ideas

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

[terryjreedy]

https://discuss.python.org/t/function-help-to-some-special-words/101625 I there suggested the alternative:

help has an interactive mode, entered with help(), in which one can enter an unquoted word (module, keyword, or topic), symbol (such as .) to get specific help, or “modules”, “keywords”,
“symbols”, or “topics” for a list of those available. It would be plausible to request that special (double-underscored, dunder) names be recognized, with “dunders” or “specials” returning a list of those recognized. In particular, help> name could give a purpose-written entry similar to that proposed above.

I believe that there have been multiple requests that help('whatever') check for special help on whatever before spewing out the 400+ pages of help on str (and without having to enter interactive help). The latter is easily available with help(''). The would, however, be a larger change.

[StanFromIreland]

This old deferred PEP may be of interest: PEP 233

[serhiy-storchaka]

I believe that there have been multiple requests that help('whatever') check for special help on whatever before spewing out the 400+ pages of help on str

It does. Try help("<") or help("int") or help("re").

But I think that it would better to stop falling back to the str class help for every other string. Better to output an error, maybe with a suggestion as for other typos.

[adqm]

But I think that it would better to stop falling back to the str class help for every other string. Better to output an error, maybe with a suggestion as for other typos.

It looks like this already happens in many (but not all) cases, e.g.:

>>> help("foo")
No Python documentation found for 'foo'.
Use help() to get the interactive help utility.
Use help(str) for help on the str class.

help("__main__") takes me to some useful docs, but help("__name__") tells me about str.

I'd be happy to have a go at this if no one else is working on it yet.