[Tutor] CONSTANTS -- Is it appropriate to use uppercase names within a function or method?

[Cameron Simpson]

On 12Nov2019 15:00, boB Stepp <robertvstepp at gmail.com> wrote:
>On Tue, Nov 12, 2019 at 1:08 PM Mats Wichmann <mats at wichmann.us> wrote:
>> On 11/12/19 10:43 AM, boB Stepp wrote:
>> ...You can
>> also configure pylint not to issue that particular warning - describing
>> how is a bit out of scope for this message.
>
>A pity.  Trying to determine how to configure pylint is what I am
>currently struggling with.  I am not finding its official
>documentation easy to comprehend.

Fortunately you don't need to rely on that. Look at the output. Here's 
an example:

    % python -m pylint --rcfile=/Users/cameron/.pylintrc --disable=bad-whitespace,invalid-name,useless-object-inheritance cs/vt/blockify.py
    ************* Module python.cs.vt.blockify
    cs/vt/blockify.py:323:10: E1307: Argument 'builtins.NoneType' does not match format type 'd' (bad-string-format-type)

and:

    % grep pylint cs/vt/blockify.py
      # pylint: disable=too-many-nested-blocks,too-many-statements
      # pylint: disable=too-many-branches,too-many-locals
            # pylint: disable=broad-except

and there's the ~/.pylintrc file referenced above.

So:

1: The error message recites the pylint rule which caused it, so 
"bad-string-format-type" is fires on line 323 of cs/vt/blockify.py.

2: You can disable specific rules for a whole file by providing them on 
the command line.

3: You can enable or disable rules for all files in a .pylintrc file.

4: You can disable specific rules for a suite in the code by preceeding 
that suite with a special "# pylint: <rule-name-here>" comment. Example:

    def blocked_chunks_of(
        chunks,
        scanner=None,
        min_block=None,
        max_block=None,
        histogram=None,
    ):
      ''' Generator which connects to a scanner of a chunk stream in
          order to emit low level edge aligned data chunks.  [...]
      '''
      # pylint: disable=too-many-nested-blocks,too-many-statements
      # pylint: disable=too-many-branches,too-many-locals
      with Pfx("blocked_chunks_of"):
        if min_block is None:
          min_block = MIN_BLOCKSIZE
        elif min_block < 8:

So my blocked_chunks_of function is rather exceptional: it is the 
performance bottleneck of the cs.vt library, and is deliberately written 
as a single huge function with several local variables because breaking 
it up brings significant performance degradation just from the function 
call overhead. There's even a C extension function to aid performance 
for the really low level part, and it still benefits from being a big 
inline function.

So this particular function turns off 4 of the pylint rules just for 
itself, leaving them active for all the other code.

Cheers,
Cameron Simpson <cs at cskk.id.au>