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2.24 Blocks

The bindings documented in this section are provided by the racket/block library, not racket/base or racket.

(block defn-or-expr ...)
Supports a mixture of expressions and mutually recursive definitions, as in a module body.

The result of the block form is the result of the last defn-or-expr if it is an expression, #<void> otherwise. If no defn-or-expr is provided (after flattening begin forms), the result is #<void>.

The final defn-or-expr is executed in tail position, if it is an expression.


  > (define (f x)
        (define y (add1 x))
        (displayln y)
        (define z (* 2 y))
        (+ 3 z)))
  > (f 12)