Re: font-lock-maximum-decoration should be 2 by default?

[Stephen J. Turnbull]

Vitalie Spinu writes:

 >   In font-lock language: If you design a feature which is intended for
 >   30% of salad lovers. Then by the virtue of emacs defaults and peoples'
 >   psychology, 90% of the people will end up using it. That is, 60% of
 >   normal users (which don't like salads) will end up eating it.

True, but it's not clear that Emacs should care about "normal" users
in the sense of "people's psychology".  Emacs users are different, at
least that's the conventional wisdom.  They like (1) customizability,
(2) a consistent user interface across applications.  It's not obvious
that the generally prevalent "accept the default" psychology is that
relevant to Emacs users.

 > 3) Developers which would like to capture 30% of salad lovers will try
 >   to find workarounds. That is, add redundant, mode-specific font-lock
 >   customization, or mess with font-lock-maximum-decoration.

This is true, but I'm not sure if it's a problem.

 > 4) If not self-obvious, the proposed modification would allow a default
 >   level of fontification. Thing which is not possible right now.

It's not obvious that the concept of "level of fontification" is
entirely consistent.  At least for me, if certain features aren't
fontified, I'm unhappy with the fontification, and if others are, I
get annoyed.  If those sets are basically monotonic across most Emacs
users, you can talk about levels.  Otherwise, what you mean by "level"
is what you mean, no more and no less.

 > 5) The most knowledgeable person to decide on the default level of font
 >   lock, is the developer of the mode. Why then emacs would decide that
 >   the maximum decoration is the best one?

This is not at all obvious.  In principle, the most knowledgeable
person to decide on the level of fontification is the user.  Then the
best default is the one that best serves the most users.  But "best
serve" is not well-defined, either.  One might think that the defaults
that require the fewest customizations by the typical user are best,
but it could easily be the case that the best defaults somehow
demonstrate the capabilities of Emacs, allowing users to learn them
with little effort, and so enabling the users to choose the ones they
like with less effort.

Whatever it is that "typical" users want, it's best decided by those
who observe the typical users.  If a mode is used by a wide variety of
users, then the Emacs maintainers are probably in the best position to
observe "typical" needs.  If a mode is used mostly by a subset of
"activists" (== users who frequently interact with the mode
maintainers) then the mode maintainers probably know best.  (Yet even
here there is a caveat: the Emacs maintainers seem likely to be most
knowledgeable about how to introduce modes to new users not already in
the activist sets.)

In the end there are arguments for both sides.