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1 point by applepie 6062 days ago | link | parent

  def make_counter():
    x = 0
    def inc():
      x = x + 1
      return x
    return inc

  c1 = make_counter()
  c1() # returns 1
That's Python.

It might seem nice at first glance :)

But... oops! it doesn't work.

It doesn't work because the "x" in "x = x + 1" is _not_ the same "x" as in "x = 0".

And that happens because definition and assignment are badly mixed up.



4 points by almkglor 6062 days ago | link

...and? The equivalent (and correctly running!) Arc code is:

  (def make-counter ()
    (let x 0
      (fn ()
        (= x (+ x 1)))))
So... why do you want to avoid 'let ?

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