97 lines
1.8 KiB
ReStructuredText
97 lines
1.8 KiB
ReStructuredText
====================
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Anaphoric Macros
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====================
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The anaphoric macros module makes functional programming in Hy very
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concise and easy to read.
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An anaphoric macro is a type of programming macro that
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deliberately captures some form supplied to the macro which may be
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referred to by an anaphor (an expression referring to another).
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-- Wikipedia (http://en.wikipedia.org/wiki/Anaphoric_macro)
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Macros
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======
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.. _ap-each:
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ap-each
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-------
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Usage: ``(ap-each [1 2 3 4 5] (print it))``
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Evaluate the form for each element in the list for side-effects.
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.. _ap-each-while:
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ap-each-while
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=============
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Usage: ``(ap-each-while list pred body)``
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Evaluate the form for each element where the predicate form returns
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True.
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.. code-block:: clojure
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=> (ap-each-while [1 2 3 4 5 6] (< it 4) (print it))
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1
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2
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3
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.. _ap-map:
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ap-map
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======
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Usage: ``(ap-map form list)``
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The anaphoric form of map works just like regular map except that
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instead of a function object it takes a Hy form. The special name,
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``it`` is bound to the current object from the list in the iteration.
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.. code-block:: clojure
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=> (list (ap-map (* it 2) [1 2 3]))
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[2, 4, 6]
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.. _ap-map-when:
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ap-map-when
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===========
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Usage: ``(ap-map-when predfn rep list)``
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Evaluate a mapping over the list using a predicate function to
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determin when to apply the form.
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.. code-block:: clojure
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=> (list (ap-map-when odd? (* it 2) [1 2 3 4]))
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[2, 2, 6, 4]
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=> (list (ap-map-when even? (* it 2) [1 2 3 4]))
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[1, 4, 3, 8]
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.. _ap-filter:
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ap-filter
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=========
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Usage: ``(ap-filter form list)``
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As with ``ap-map`` we take a special form instead of a function to
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filter the elements of the list. The special name ``it`` is bound to
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the current element in the iteration.
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.. code-block:: clojure
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=> (list (ap-filter (> (* it 2) 6) [1 2 3 4 5]))
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[4, 5]
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