(fn slice (list idx) (do
    (let list_len (len list))
    (let elems (list))
    (let i idx)
    (loop (do
        (if (>= i list_len) (break))
        (push elems (at list i))
        (+= i 1)
    ))
    (return elems)
))

(fn slice_eq (str slice_idx substr) (do
    (let str_len (len str))
    (let substr_len (len substr))
    (let i 0)
    (loop (do
        (if (>= i substr_len)
            (return true))
        (if (>= (+ slice_idx i) str_len)
            (return false))
        (if (!= (at str (+ slice_idx i)) (at substr i))
            (return false))
        (+= i 1)
    ))
    (return true)
))


(fn contains (text ch) (do
    (let text_len (len text))
    (let i 0)
    (loop (do
        (if (>= i text_len) (break))
        (if (== (at text i) ch) (do
            (return true)
        ))
        (+= i 1)
    ))
    (return false)
))

(fn indent (depth) (do
    (let space "")
    (let i 0)
    (loop (do
        (if (>= i depth) (break))
        (+= space "  ")
        (+= i 1)
    ))
    (return space)    
))