Maybe gretl should be stricter in not allowing built-in function
names as identifiers. (Again, I think that was discussed before with
the conclucsion that it's not a problem per se.)
# y is described as lag of 'sin'
Good catch, this is the bug.
# but
# i.e. y is a constant series, its values are equal to
sin(1)
This is expected I'd say.
BTW, here's something else:
series y = normal()
series y = y[-1]
...gives NAs (note the square brackets, on purpose). I think it
should give an error.
cheers,
sven