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match



    macro
    boot.janet on line 1580, column 1

    (match x & cases)

    Pattern matching. Match an expression `x` against any number of
    cases. Each case is a pattern to match against, followed by an
    expression to evaluate to if that case is matched. Legal patterns
    are:

    * symbol -- a pattern that is a symbol will match anything, binding
      `x`'s value to that symbol.

    * array -- an array will match only if all of its elements match the
      corresponding elements in `x`.

    * table or struct -- a table or struct will match if all values match
      with the corresponding values in `x`.

    * tuple -- a tuple pattern will match if its first element matches,
      and the following elements are treated as predicates and are true.

    * `_` symbol -- the last special case is the `_` symbol, which is a
      wildcard that will match any value without creating a binding.

    Any other value pattern will only match if it is equal to `x`.

See also:case1 exampleSign in to add an example

(def a-tuple-1 [:number 10])
(def a-tuple-2 [:string "Hello there!"])
(defn show [what]
  (match what
    [:number n] (printf "It's a number! %d" n)
    [:string s] (printf "Here's a string: %s" s)
    _ (printf "I dunno what this is: %q" what)))

(show a-tuple-1)
(show a-tuple-2)
(show [:array @[]])

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