Hyskell

This brings two functional-ish things to Hy: accumulating for loops and unions/pattern matching. Just prefix your files with this:

.. code-block:: hy

(require hyskell)

accfor

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accfor is a for loop that is actually an iterator. It's basically genexpr with a nicer syntax that can take anything; not just a single expression.

.. code-block:: hy

(print (list (accfor [x [1 2 3]] x))) ; prints [1 2 3]

defunion

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Defines a union type:

.. code-block:: hy

(defunion Node (Nint val) (Nstr val))

This example defines three types: Node (a base class), Nint (a class with one attribute: val), and Nstr (same as Nint).

You can use the types like any other type:

.. code-block:: hy

(setv i (Nint 7)) (setv s (Nstr "abc"))

match

---

True ML-style pattern matching:

.. code-block:: hy

(match value [[1 2 3] (print "Got list [1 2 3]")] ; against a list [[:a 2 3] (print "Got list with a =" a)] ; grab values with : [(, 1 2) (print "Got tuple (1, 2)")] ; against a tuple [1 (print "Got 1")] ; against an int or string [(Nint :v) (print "Got Nint with v =" v)] ; against a union branch [(Nstr (:val "abc")) (print "Got Nstr with val of abc")] ; use : at the beginning of an expression to test attributes [(Nstr ) (print "Got Nstr")] ; use _ to ignore values [[1 2 ...] (print "Got list that starts with 1 and 2")] ; use ... to allow extra items at the end [[ _ ...] (print "Got list with >= 2 elements")] ; use ... with _ to do cool stuff [_ (print "Got something weird!")]) ; you can also use _ for a fallthrough statement

If none of the branches match, a hyskell.MatchFailure exception is thrown.

Examples

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See test_hyskell.hy for the unit tests, written using HyTest <https://github.com/kirbyfan64/hytest>_.