Two newbie questions

[Palmer, Ralph]

Greetings -

Nice program! I was using .abc, with abcm2ps (which I still like for its
ease of use and speed of entry), but LilyPond seems even more flexible.
I think I still prefer .abc for some scores, but there are things I can
do in LilyPond that I can't do in .abc.

1) What's LSR?

2) What's the significance of an embedded space? Or, perhaps more to the
point, where are embedded spaces (or line returns, for that matter)
prohibited (or significant)? It's clear there are places where adding an
embedded space mucks things up (like between a note name and and a slur
start, for example), and places where it seems to make no difference to
LilyPond; is there a simple rule that distinguishes the two categories?

Ralph Palmer