macro
boot.janet on line 158, column 1
(assert x &opt err)
Throw an error if x is not truthy. Will not evaluate `err` if x is
truthy.
(assert :dude :what?) # => :dude
(assert :dude :dude) # => :dude
(assert (= :dude :what?) "Where's my car?")
# => error: Where's my car?
# => in _thunk [repl] (tailcall) on line 84, column 1
(assert (= :dude :dude) "Where's my car?") # => true
(var a 0)
(assert (pos? a) "A is definitely not positive")
# error: A is definitely not positive
# in assert [boot.janet] on line 149, column 11
# in _thunk [repl] (tailcall) on line 3, column 1