1  #!/usr/bin/env python
 2  # vim: sts=4 sw=4 et
 3  
 4  """
 5  
 6  This module allows the creation of userspace HAL components in Python.
 7  This includes pins and parameters of the various HAL types.
 8  
 9  Typical usage:
10  
11  import hal, time
12  h = hal.component("component-name")
13  # create pins and parameters with calls to h.newpin and h.newparam
14  h.newpin("in", hal.HAL_FLOAT, hal.HAL_IN)
15  h.newpin("out", hal.HAL_FLOAT, hal.HAL_OUT)
16  h.ready() # mark the component as 'ready'
17  
18  try:
19      while 1:
20          # act on changed input pins; update values on output pins
21          time.sleep(1)
22          h['out'] = h['in']
23  except KeyboardInterrupt: pass
24  
25  
26  When the component is requested to exit with 'halcmd unload', a
27  KeyboardInterrupt exception will be raised.
28  """
29  
30  import _hal
31  from _hal import *
32  
33  class _ItemWrap(object):
34      def __new__(cls, item):
35          if not isinstance(item, _hal.item):
36              raise TypeError("Constructor argument must be _hal.item: %s" % type(item))
37          self = super(_ItemWrap, cls).__new__(cls)
38          return self._item_wrap(item)
39  
40      def _item_wrap(self, item):
41          for f in ['get', 'set', 'get_type', 'get_name', 'get_dir', 'is_pin', '__repr__']:
42              setattr(self, f, getattr(item, f))
43          return self
44  
45      def __init__(self, item):
46          self._item = item
47  
48      name = property(lambda s: s._item.get_name())
49      type = property(lambda s: s._item.get_type())
50      dir  = property(lambda s: s._item.get_dir())
51  
52      value = property(lambda s: s._item.get(), lambda s,v: s._item.set(v))
53  
54  class Pin(_ItemWrap):
55      def __init__(self, item):
56          _ItemWrap.__init__(self, item)
57          if not item.is_pin():
58              raise TypeError("Must be constructed from pin object")
59  
60  class Param(_ItemWrap):
61      def __init__(self, item):
62          _ItemWrap.__init__(self, item)
63          if item.is_pin():
64              raise TypeError("Must be constructed from param object")
65  
66  class component(_hal.component):
67      def newpin(self, *a, **kw): return Pin(_hal.component.newpin(self, *a, **kw))
68      def newparam(self, *a, **kw): return Param(_hal.component.newparam(self, *a, **kw))
69  
70      def getpin(self, *a, **kw): return Pin(_hal.component.getpin(self, *a, **kw))
71      def getparam(self, *a, **kw): return Param(_hal.component.getparam(self, *a, **kw))