RosettaCodeData/Task/Call-an-object-method/LFE/call-an-object-method-3.lfe

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(defmodule object
(export all))
(defun fish-class (species)
"
This is the constructor that will be used most often, only requiring that
one pass a 'species' string.
When the children are not defined, simply use an empty list.
"
(fish-class species ()))
(defun fish-class (species children)
"
This constructor is useful for two reasons:
1) as a way of abstracting out the id generation from the
larger constructor, and
2) spawning the 'object loop' code (fish-class/3).
"
(let* (((binary (id (size 128))) (: crypto rand_bytes 16))
(formatted-id (car
(: io_lib format
'"~32.16.0b" (list id)))))
(spawn 'object
'fish-class
(list species children formatted-id))))
(defun fish-class (species children id)
"
This function is intended to be spawned as a separate process which is
used to track the state of a fish. In particular, fish-class/2 spawns
this function (which acts as a loop, pattern matching for messages).
"
(let ((move-verb '"swam"))
(receive
((tuple caller 'move distance)
(! caller (list species move-verb distance))
(fish-class species children id))
((tuple caller 'species)
(! caller species)
(fish-class species children id))
((tuple caller 'children)
(! caller children)
(fish-class species children id))
((tuple caller 'children-count)
(! caller (length children))
(fish-class species children id))
((tuple caller 'id)
(! caller id)
(fish-class species children id))
((tuple caller 'info)
(! caller (list id species children))
(fish-class species children id))
((tuple caller 'reproduce)
(let* ((child (fish-class species))
(child-id (get-id child))
(children-ids (: lists append
(list children (list child-id)))))
(! caller child)
(fish-class species children-ids id))))))
(defun call-method (object method-name)
"
This is a generic function, used to call into the given object (class
instance).
"
(! object (tuple (self) method-name))
(receive
(data data)))
(defun call-method (object method-name arg)
"
Same as above, but with an additional argument.
"
(! object (tuple (self) method-name arg))
(receive
(data data)))
; define object methods
(defun get-id (object)
(call-method object 'id))
(defun get-species (object)
(call-method object 'species))
(defun get-info (object)
(let ((data (call-method object 'info)))
(: io format '"id: ~s~nspecies: ~s~nchildren: ~p~n" data)))
(defun move (object distance)
(let ((data (call-method object 'move distance)))
(: io format '"The ~s ~s ~p feet!~n" data)))
(defun reproduce (object)
(call-method object 'reproduce))
(defun get-children (object)
(call-method object 'children))
(defun get-children-count (object)
(call-method object 'children-count))