(pad st len (? ch \space))
  st: a str
  len: an int
  ch: a char (optional)
  returns a str
F

Adds padding characters to the end of a string.

Returns a newly-allocated, mutable string which contains at least len characters. If st is shorter than len, any missing characters are filled in with ch.

(ensure (eq? (pad "hello" 4) "hello"))
(ensure (eq? (pad "hello" 8) "hello   "))
(ensure (eq? (pad "hello" 8 \o) "helloooo"))
←trim-end
⭡
pad-start→