[Python-Dev] Re: PEP 285: Adding a bool type (original) (raw)

Andrew Koenig ark@research.att.com
03 Apr 2002 12:36:14 -0500

I mean that the language doesn't prefer a single way, as opposed to programmers' conventions.

Fredrik> it's more than just a convention -- built-in functions and Fredrik> operators always return 0 for false and 1 for true whenever Fredrik> they need to invent a boolean value. this is documented in Fredrik> the language reference.

On the other hand, the library isn't nearly so consistent. Just for fun, I started browsing the library documentation at random.

The very first page I visited was the description of gc, the garbage collector interface. The first function that returns a truth value there is described as

    isenabled()
        Returns true if automatic collection is enabled.

Some more examples:

    2.2.6.1 String Methods

    endswith(suffix[,start[,end]])
        Return true if the string ends with the specified suffix,
        otherwise return false.

    Similarly for isalnum, isalpha, isdigit, islower, isspace.

    2.2.8 File Objects:

    isatty()
        Return true if the file is connected to a tty(-like) device,
        else false.

    6.2 os.path -- Common pathname manipulations

    exists(path)
        Return true if path refers to an existing path.

I'm sure there are others.

-- Andrew Koenig, ark@research.att.com, http://www.research.att.com/info/ark