Re: M-g in dired

[Juri Linkov]

>> This docstring is not very clear.  The documentation in the Emacs Lisp
>> is better:
>
>>   If the string or vector KEY is not a valid key sequence according to
>>   the prefix keys specified in KEYMAP, it must be "too long" and have
>>   extra events at the end that do not fit into a single key sequence.
>>   Then the value is a number, the number of events at the front of KEY
>>   that compose a complete key.
>
>> For the case of dired-mode-map where lookup-key returns 1 for "\C-x`",
>> 1 is not a number of events at the front of "\C-x`" that compose
>> a complete key, because "C-x" alone is not a valid key in dired-mode-map.
>
> It doesn't say "valid key" it says "valid key sequence".  "C-x" is a valid
> key sequence in this context.  It is not bound to anything, but it is
> a valid sequence.  C-x ` is not a valid sequence on the other hand, because
> read-key-sequence would have immediately stopped after C-x.

>From the docstring I understood that "valid key sequence" means
a valid and bound key sequence, due to the sentence:

  The number is how many characters at the front of key it takes
  to reach a non-prefix command.

To me "a non-prefix command" implies a bound command key sequence.
That's why I changed the code to return the integer value only
on the condition `if (!NILP (cmd))'.

However, if this is not what the docstring meant, and leaving the logic
of the current return value is desirable, then maybe `lookup-key' needs
an additional argument defining another logic of its return value.

Otherwise, almost all code in `lookup-key' should be duplicated in
`shadow_lookup'.

-- 
Juri Linkov
http://www.jurta.org/emacs/