Improvements

.travis.yml

@@ -7,6 +7,7 @@ python:
   - "2.7"
   - "3.3"
   - "3.4"
+  - "3.5"
 
 env:
   - PINT="N" PYVISA='N'

lantz_core/backends/visa.py

@@ -399,7 +399,7 @@ class VisaMessageDriver(BaseVisaDriver):
     def read_status_byte(self):
         return byte_to_dict(self._resource.read_stb(), self.STATUS_BYTE)
 
-    def default_get_feature(self, iprop, cmd, *args, **kwargs):
+    def default_get_feature(self, feat, cmd, *args, **kwargs):
         """Query the value using the provided command.
 
         The command is formatted using the provided args and kwargs before
@@ -408,7 +408,7 @@ def default_get_feature(self, iprop, cmd, *args, **kwargs):
         """
         return self._resource.query(cmd.format(*args, **kwargs))
 
-    def default_set_feature(self, iprop, cmd, *args, **kwargs):
+    def default_set_feature(self, feat, cmd, *args, **kwargs):
         """Set the iproperty value of the instrument.
 
         The command is formatted using the provided args and kwargs before

lantz_core/channel.py → lantz_core/base_channel.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 """
-    lantz_core.channel
-    ~~~~~~~~~~~~~
+    lantz_core.base_channel
+    ~~~~~~~~~~~~~~~~~~~~~~~
 
     Channel simplifies the writing of instrument implementing channel specific
     behaviours.
@@ -14,7 +14,7 @@
                         absolute_import)
 
 from .has_features import AbstractChannel
-from .subsystem import SubSystem
+from .base_subsystem import SubSystem
 
 
 class Channel(SubSystem):
@@ -91,29 +91,40 @@ class ChannelContainer(object):
     name : unicode
         Name of the channel subpart on the parent.
 
-    list_available : unicode
-        Name of the parent method to use to query the available channels.
+    list_available : callable
+        Function to call to query the list of available channels.
+
+    aliases : dict
+        Dict mapping aliases names to the real channel id to use.
 
     """
 
-    def __init__(self, cls, parent, name, available):
+    def __init__(self, cls, parent, name, list_available, aliases):
         self._cls = cls
         self._channels = {}
         self._name = name
         self._parent = parent
-        if isinstance(available, (tuple, list)):
-            self._list = lambda: available
-        else:
-            self._list = getattr(parent, available)
+        self._aliases = aliases
+        self._list = list_available
 
     @property
     def available(self):
         """List the available channels.
 
         """
-        return self._list()
+        return self._list(self._parent)
+
+    @property
+    def aliases(self):
+        """List the aliases.
+
+        """
+        return self._aliases.copy()
 
     def __getitem__(self, ch_id):
+        if ch_id in self._aliases:
+            ch_id = self._aliases[ch_id]
+
         if ch_id in self._channels:
             return self._channels[ch_id]
 

lantz_core/subsystem.py → lantz_core/base_subsystem.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 """
-    lantz_core.subsystem
-    ~~~~~~~~~~~~~~~~~~~~
+    lantz_core.base_subsystem
+    ~~~~~~~~~~~~~~~~~~~~~~~~~
 
     Subsystems can be used to give a hierarchical organisation to a driver.
 

lantz_core/features/__init__.py

@@ -15,5 +15,8 @@
 from .bool import Bool
 from .scalars import Unicode, Int, Float
 from .register import Register
+from .alias import Alias
+from .util import constant, conditional
 
-__all__ = ['Bool', 'Unicode', 'Int', 'Float', 'Register']
+__all__ = ['Bool', 'Unicode', 'Int', 'Float', 'Register', 'Alias', 'constant',
+           'conditional']

lantz_core/features/alias.py

@@ -0,0 +1,82 @@
+# -*- coding: utf-8 -*-
+"""
+    lantz_core.features.alias
+    ~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    Feature whose value is mapped to another Feature.
+
+    :copyright: 2015 by Lantz Authors, see AUTHORS for more details.
+    :license: BSD, see LICENSE for more details.
+
+"""
+from __future__ import (division, unicode_literals, print_function,
+                        absolute_import)
+
+from types import MethodType
+
+from future.utils import exec_
+
+from .feature import Feature, get_chain, set_chain
+
+
+GET_DEF =\
+"""def get(self, driver):
+    return {}
+
+"""
+
+
+SET_DEF =\
+"""def set(self, driver, value):
+    {} = value
+
+"""
+
+
+class Alias(Feature):
+    """Feature whose value is mapped to another Feature.
+
+    """
+
+    def __init__(self, alias, settable=None):
+
+        super(Alias, self).__init__(True, settable)
+
+        accessor = 'driver.' + '.'.join([p if p else 'parent'
+                                         for p in alias.split('.')])
+
+        defs = GET_DEF.format(accessor)
+        if settable:
+            defs += '\n' + SET_DEF.format(accessor)
+
+        loc = {}
+        exec_(defs, globals(), loc)
+
+        self.get = MethodType(loc['get'], self)
+        if settable:
+            self.set = MethodType(loc['set'], self)
+
+    def post_set(self, driver, value, i_value, response):
+        """Re-implemented here as an Alias does not need to do anaything
+        by default.
+
+        """
+        pass
+
+    # =========================================================================
+    # --- Private API ---------------------------------------------------------
+    # =========================================================================
+
+    def _get(self, driver):
+        """Re-implemented so that Alias never use the cache.
+
+        """
+        with driver.lock:
+            return get_chain(self, driver)
+
+    def _set(self, driver, value):
+        """Re-implemented so that Alias never uses the cache.
+
+        """
+        with driver.lock:
+            set_chain(self, driver, value)

lantz_core/features/feature.py

@@ -11,11 +11,13 @@
 """
 from __future__ import (division, unicode_literals, print_function,
                         absolute_import)
+
 from types import MethodType
 from collections import OrderedDict
 from stringparser import Parser
 
-from .util import wrap_custom_feat_method, MethodsComposer, COMPOSERS
+from .util import (wrap_custom_feat_method, MethodsComposer, COMPOSERS,
+                   AbstractGetSetFactory)
 from ..errors import LantzError
 from ..util import build_checker
 
@@ -68,7 +70,7 @@ class Feature(property):
     discard : tuple or dict
         Tuple of names of features whose cached value should be discarded after
         setting the Feature or dictionary specifying a list of feature whose
-        cache should be discarded under the 'feature' key and a list of limits
+        cache should be discarded under the 'features' key and a list of limits
         to discard under the 'limits' key.
 
     Attributes
@@ -87,8 +89,7 @@ def __init__(self, getter=None, setter=None, extract='', retries=0,
         self._setter = setter
         self._retries = retries
         self._customs = {}
-        # Don't create the weak values dict if it is not used.
-        self._proxies = ()
+
         self.creation_kwargs = {'getter': getter, 'setter': setter,
                                 'retries': retries, 'checks': checks,
                                 'extract': extract, 'discard': discard}
@@ -98,6 +99,11 @@ def __init__(self, getter=None, setter=None, extract='', retries=0,
                              self._set if setter is not None else None,
                              self._del)
 
+        if isinstance(getter, AbstractGetSetFactory):
+            self.get = MethodType(getter.build_getter(), self)
+        if isinstance(setter, AbstractGetSetFactory):
+            self.set = MethodType(setter.build_setter(), self)
+
         if checks:
             self._build_checkers(checks)
         if discard:

lantz_core/features/register.py

@@ -46,8 +46,7 @@ def __init__(self, getter=None, setter=None, names=(), length=8,
             # Makes sure every key is unique by using the bit index if None is
             # found
             for i, n in enumerate(names[:]):
-                if n is None:
-                    names[i] = i
+                names[i] = n or i
 
         self.names = tuple(names)
         self.creation_kwargs['names'] = names

lantz_core/features/util.py

@@ -11,9 +11,12 @@
 """
 from __future__ import (division, unicode_literals, print_function,
                         absolute_import)
+
 from types import MethodType
 from functools import update_wrapper
 
+from future.utils import exec_
+
 
 def wrap_custom_feat_method(meth, feat):
     """ Wrap a HasFeature method to make it an driver method of a Feature.
@@ -333,3 +336,125 @@ def decorator(function):
         return function
 
     return decorator
+
+# --- Getter/setter factories -------------------------------------------------
+
+
+class AbstractGetSetFactory(object):
+    """Abstract class for get/set factories.
+
+    Use by Feature to identify such a factory and use it to replace the
+    get/set method.
+
+    """
+
+    def build_getter(self):
+        """Build the function for getting the Feature value.
+
+        This method is called when a get/set factory is passed as the getter
+        argument to a Feature.
+
+        """
+        raise NotImplementedError()
+
+    def build_setter(self):
+        """Build the function for setting the Feature value.
+
+        This method is called when a get/set factory is passed as the setter
+        argument to a Feature.
+
+        """
+        raise NotImplementedError()
+
+
+class constant(AbstractGetSetFactory):
+    """Make a Feature return always the same value.
+
+    This can only be used as a getter factory.
+
+    Parameters
+    ----------
+    value :
+        The value the Feature should return
+
+    """
+
+    def __init__(self, value):
+        super(constant, self).__init__()
+        self._value = value
+
+    def build_getter(self):
+        """Build a trivial function to return the constant value.
+
+        """
+        value = self._value
+
+        def getter(self, driver):
+            return value
+
+        return getter
+
+
+GET_DEF =\
+"""def get(self, driver):
+    val = {}
+    return {}
+
+"""
+
+SET_DEF =\
+"""def set(self, driver, value):
+    cmd = {}
+    return driver.default_set_feature(self, cmd, value)
+"""
+
+
+class conditional(AbstractGetSetFactory):
+    """Make a Feature modify getting/setting based on the driver state.
+
+    Parameters
+    ----------
+    conditional_value : unicode
+        String of the form 'a if driver.b else c'. When setting the value is
+        accessible as value.
+
+    default : bool
+        Pass the result of the conditional evalutation to the
+        default_get/set_feature method of the driver if True, otherwise
+        directly return the result.
+        When building a setter this MUST be true.
+
+    """
+
+    def __init__(self, conditional_value, default=False):
+        super(conditional, self).__init__()
+        self._cond = conditional_value
+        self._default = default
+
+    def build_getter(self):
+        """Build the getter.
+
+        """
+        if not self._default:
+            get_def = GET_DEF.format(self._cond, 'val')
+
+        else:
+            get_def = GET_DEF.format(self._cond,
+                                     'driver.default_get_feature(self, val)')
+
+        loc = {}
+        exec_(get_def, globals(), loc)
+
+        return loc['get']
+
+    def build_setter(self):
+        """Build the setter.
+
+        """
+        if not self._default:
+            raise ValueError('Can build a setter only if default is True')
+
+        loc = {}
+        exec_(SET_DEF.format(self._cond), globals(), loc)
+
+        return loc['set']