ffc.syn		is the base version of ffcalc.syn from the examples.
ffc-d.syn	sets "distinguish lexemes"
ffc-r.syn	sets "reentrant parser"
ffc-re.syn	sets "reentrant parser" and "event driven"
ffc-rp.syn	sets "reentrant parser" and "pointer input"
ffc-t.syn	sets "traditional engine"
ffc-w.syn	sets "wrapper"
ffc-wa.syn	sets "wrapper", "auto resynch", and "error frame"

ffcx.syn	is the base version of ffcalcx.syn from the examples.
ffcx-t.syn	sets "traditional engine"

ffcm.syn	is some weirdly mangled version of ffcalc
ffcm-a.syn	is a small modification to it
ffcm-b.syn	is a larger modification to it

ffcs-t.syn	uses different syntax (and sets "traditional engine")

number.h	is used by ffc-w and ffc-wa.

input/test.ffc	is the test file from the examples.
input/test2.ffc	is a version with a few more things.
input/test3.ffc	is a version with different spacing.
input/test4.ffc	is a version of test3 with a syntax error.