\set - \override #(set

[Damian leGassick]

Hi all

I've been using lilypond for years but I still can't figure out the rationale 
for

e.g.

bar numbers - why us it:

\override Score.BarNumber #'break-visibility blah (note capital B)

but

\set Score.currentBarNumber #blah (note camelCase)

and why #(set-accidental-style etc

and not

\set Score.accidentalStyle or even \set Score.Accidental style

is there any easy way to remember whether it's \set \override or #(set*?

tia

Damian