unrecognized syntax: type[args]

[Damien Mattei <damien.mattei@gmail.com>]

#|kawa:11|# (define (copy-stepped-slice container-eval expr-eval i1 i2 step)
#|.....12|#
#|.....13|#   (when (= step 0)
#|.....14|#     (error "assignment : slice step cannot be zero"))
#|.....15|#
#|.....16|#   (<+ i 0)
#|.....17|#
#|.....18|#   (if (< step 0) ;; with negative index we start at end of
vector (like in Python)
#|.....19|#       (for ((<+ k i2) (>= k i1) (<- k (+ k step)))
#|.....20|#        (<- ($bracket-apply$ container-eval k)
($bracket-apply$ expr-eval i))
#|.....21|#        (<- i (+ i 1)))
#|.....22|#
#|.....23|#       (for ((<+ k i1) (< k i2) (<- k (+ k step)))
#|.....24|#        (<- ($bracket-apply$ container-eval k)
($bracket-apply$ expr-eval i))
#|.....25|#        (<- i (+ i 1)))))
/dev/tty:20:44: unrecognized syntax: type[args]
/dev/tty:24:44: unrecognized syntax: type[args]


what does it means?