bug#17559: 24.3.50; Partial completion does not complete underscore delimited input

[Stefan Monnier <monnier@iro.umontreal.ca>]

retitle 17559 `initials' does not complete underscore delimited input
severity 17559 wishlist
thanks

> The documentation for the customizable variable
> `completion-pcm-word-delimiters' states:
> ``"A string of characters treated as word delimiters for completion.''
> The default value contains _ , yet it does not seem to work, i.e.

This variable just means that "a_b_c" can be completed by
`partial-completion' style to "alonzo_bob_church" and indeed, that
works, AFAICT.

> (let ((completion-styles '(partial)))
>   (completion-initials-all-completions "fdh" '("friss_die_haelfte") nil 0))

[ completion-styles is used to decide which completion-*-all-completions
  to call, but completion-initials-all-completions should be unaffected by
  completion-styles (and indeed, it isn't, and `partial' is not a valid
  completion style, AFAIK). ]

> => nil

Indeed, completion-initials-all-completions hard-codes "-" as the
separator (you can see it in completion-initials-expand).


        Stefan