It's been a year, but I'm finally calling it 0.1.0 - see attachment. I've updated the original post with the new supported commands, but importantly this version is capable of running STxAxTIC's sxript language!
This version can create SUBs and FUNCTIONs, with the catch that if you put the SUB/FUNCTION at the bottom of your program, you'll need a DECLARE SUB or DECLARE FUNCTION line at the top. Or, just put the SUB itself at the top of your program (that's perfectly legal in L-BASIC).
You can also have optional arguments! Example:
sub s(a, option b, option c)
print "a = "; a;
if option(b) then print "b = "; b;
if option(c) then print "c = "; c;
print
end sub
s 1
s 2, 3
s 2, 3, 4
s 2, , 4
Other working features include array resizing including _preserve, and DIM SHARED support.