Re: Naming predicates (was: master d0c77a1: Remove some assumptions about timestamp format)

[Paul Eggert]

On 9/28/18 11:28 AM, Drew Adams wrote:
>    If the purpose of a function is to tell you whether a certain
>    condition is true or false, give the function a name that ends in
>    'p' (which stands for "predicate").  If the name is one word, add
>    just 'p'; if the name is multiple words, add '-p'.  Examples are
>    'framep' and 'frame-live-p'.

Thanks for the pointer; I'd forgotten that. But there are several 
counterexamples:

indivisible-p interactive-p ring-p registerv-p

and lots more counterexamples the other way:

bool-vector-subsetp coding-system-lessp default-boundp 
file-attributes-lessp hack-one-local-variable-eval-safep ...

Plus lots more symbols taken from Common Lisp, like cl-equalp.

The Common Lisp influence seems to be causing a lot of Elisp code to 
violate the guideline, which may help to explain why I can never 
remember it.