$print-vector-with-brackets
special-variable
When true, vectors are printed like [...] otherwise like #v(...).
make-html > (do
(let $print-vector-with-brackets true)
(write-line (vector 'a 'b 'c)))
[a b c]
make-html > (do
(let $print-vector-with-brackets false)
(write-line (vector 'a 'b 'c)))
#v(a b c)