Re: feature/type-hierarchy 8a63e50036f 1/5: * Define 'cl--type-hierarchy' and compute 'cl--typeof-types' from it

[Andrea Corallo]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> -(defconst cl--typeof-types
>> -  ;; Hand made from the source code of `type-of'.
>> -  '((integer number integer-or-marker number-or-marker atom)
>> -    (symbol-with-pos symbol atom) (symbol atom) (string array sequence atom)
> [...]
>> +(defconst cl--type-hierarchy
> [...]
>> +    (symbol keyword boolean symbol-with-pos)
> [...]
>> +    (symbol-with-pos keyword))
>
> How did you come up with `cl--type-hierarchy`?
> Because, obviously, something changed here.
> How is `keyword` a "direct subtype" of `symbol-with-pos`?

Hi Stefan,

Can't we have keyword that is a symbol-with-pos as well?

>> +(defconst cl--direct-supertypes-of-type
>> +  (make-hash-table :test #'eq)
>> +  "Hash table TYPE -> SUPERTYPES.")
>> +
>> +(defconst cl--direct-subtypes-of-type
>> +  (make-hash-table :test #'eq)
>> +  "Hash table TYPE -> SUBTYPES.")
>> +
>> +(cl-loop for (parent . children) in cl--type-hierarchy
>> +         do (cl-loop
>> +             for child in children
>> +             do (cl-pushnew parent (gethash child 
>> cl--direct-supertypes-of-type))
>> +             do (cl-pushnew child (gethash parent 
>> cl--direct-subtypes-of-type))))
>
> FWIW, I think we should create a "type descriptor" defstruct (from which
> `cl--class` would inherit), and generalize the `cl--class` symbol
> property to one that holds the type descriptor of the given name.
>
> So you could get the direct parents of `integer` with something like:
>
>     (slot-value (get 'integer 'cl--class) 'parents)
>
> [ And then `C-h o integer RET` should show the corresponding info.  ]

SGTM, I'm not very accustomed to this area of the code tho.

>> +(defconst cl--typeof-types nil
>
> This can't make sense.
> If you change it later with `push/setq` it should not be a "defconst".
> So either arrange to compute its default value directly inside the
> `defconst`, or use a `defvar`.

Ops done.

>> +(maphash (lambda (type _)
>> +           (push (cl--supertypes-for-typeof-types type) cl--typeof-types))
>> +         cl--direct-supertypes-of-type)
>
> Did you compare the resulting alist to the one we had before?
> Remember that the order of "(direct or not) supertypes" in there is
> important.
> The current table has errors.  I see for example:
>
>     (fixnum integer integer-or-marker number atom number-or-marker)
>
> where `atom` should come *after* `number-or-marker`.

Yes I did it but I missed this sorry. I wish this was catch-ed in the
two weeks this branch stayed in review.  Okay in my todo list now for
the weekend :)

Thanks

  Andrea