[luatex] ligatures with luaotfload

[Javier Múgica de Rivera]

I have used the luaotfload package for the first time, and worte the
following code in order to do so:

%def\otffont#1=#2 at{\font#1={#2: mode=base;tlig;trep} at}
\def\otffont#1=#2 at{\font#1={#2: mode=node;tlig;trep} at}

\otffont\tenrm=LMRoman10-Regular at 10pt

The font appears to be right at first sight but looking closer I see
that kerning and ligatures are missing. How can that be solved?

Another issue is the tlig and trep substitutions. If I write
``hello'', I get the right output if I use the node mode, but if I use
the base mode I have to remove the trep option in order to get it
right, otherwise what I get is two consecutive single-left-quotes. It
seems that the package in base mode first applies the option trep,
replacing the each ` with a quote, and then tlig is useless since the
couple `` of original input characters is already gone. Since I
perceived no differences between base and node modes I simply switched
to node mode.

Regards,
Javier A. Múgica