(forn clause ..body)
  clause: an arr
  body: zero or more forms
M

Loops over a numeric range.

clause must contain a symbol, followed by one to three argument forms.

(forn (i x y) form0 form1) is equivalent to:

(for i in (rn x y)
  form0
  form1)

See also: for, forni, rn

for
forni