[Python-Dev] Re: PEP 285: Adding a bool type

[Andrew Koenig]

>> 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