Use the multidict in the python config stuff. Makes code a bit

cleaner.

python/m5/config.py:
    Use the multidict instead of the separately coded _getparam
    and _getvalue stuff.  While we're at it, when we see a default
    parameter, we stick it into the dictionary right away.

--HG--
extra : convert_revision : d6f6f5cc454a479e27718ec7952cd7559229ebe7

python/m5/multidict.py

@@ -0,0 +1,158 @@
+__all__ = [ 'multidict' ]
+
+class multidict(object):
+    __nodefault = object()
+    def __init__(self, parent = {}, **kwargs):
+        self.dict = dict(**kwargs)
+        self.parent = parent
+        self.deleted = {}
+
+    def __str__(self):
+        return str(dict(self.items()))
+
+    def __repr__(self):
+        return `dict(self.items())`
+
+    def __contains__(self, key):
+        return self.dict.has_key(key) or self.parent.has_key(key)
+
+    def __delitem__(self, key):
+        try:
+            del self.dict[key]
+        except KeyError, e:
+            if key in self.parent:
+                self.deleted[key] = True
+            else:
+                raise KeyError, e
+
+    def __setitem__(self, key, value):
+        self.deleted.pop(key, False)
+        self.dict[key] = value
+
+    def __getitem__(self, key):
+        try:
+            return self.dict[key]
+        except KeyError, e:
+            if not self.deleted.get(key, False) and key in self.parent:
+                return self.parent[key]
+            else:
+                raise KeyError, e
+
+    def __len__(self):
+        return len(self.dict) + len(self.parent)
+
+    def next(self):
+        for key,value in self.dict.items():
+            yield key,value
+
+        if self.parent:
+            for key,value in self.parent.next():
+                if key not in self.dict and key not in self.deleted:
+                    yield key,value
+
+    def has_key(self, key):
+        return key in self
+
+    def iteritems(self):
+        for item in self.next():
+            yield item
+
+    def items(self):
+        return [ item for item in self.next() ]
+
+    def iterkeys(self):
+        for key,value in self.next():
+            yield key
+
+    def keys(self):
+        return [ key for key,value in self.next() ]
+
+    def itervalues(self):
+        for key,value in self.next():
+            yield value
+
+    def values(self):
+        return [ value for key,value in self.next() ]
+
+    def get(self, key, default=__nodefault):
+        try:
+            return self[key]
+        except KeyError, e:
+            if default != self.__nodefault:
+                return default
+            else:
+                raise KeyError, e
+
+    def setdefault(self, key, default):
+        try:
+            return self[key]
+        except KeyError:
+            self.deleted.pop(key, False)
+            self.dict[key] = default
+            return default
+
+    def _dump(self):
+        print 'multidict dump'
+        node = self
+        while isinstance(node, multidict):
+            print '    ', node.dict
+            node = node.parent
+
+    def _dumpkey(self, key):
+        values = []
+        node = self
+        while isinstance(node, multidict):
+            if key in node.dict:
+                values.append(node.dict[key])
+            node = node.parent
+        print key, values
+
+if __name__ == '__main__':
+    test1 = multidict()
+    test2 = multidict(test1)
+    test3 = multidict(test2)
+    test4 = multidict(test3)
+
+    test1['a'] = 'test1_a'
+    test1['b'] = 'test1_b'
+    test1['c'] = 'test1_c'
+    test1['d'] = 'test1_d'
+    test1['e'] = 'test1_e'
+
+    test2['a'] = 'test2_a'
+    del test2['b']
+    test2['c'] = 'test2_c'
+    del test1['a']
+
+    test2.setdefault('f', multidict)
+
+    print 'test1>', test1.items()
+    print 'test2>', test2.items()
+    #print test1['a']
+    print test1['b']
+    print test1['c']
+    print test1['d']
+    print test1['e']
+
+    print test2['a']
+    #print test2['b']
+    print test2['c']
+    print test2['d']
+    print test2['e']
+
+    for key in test2.iterkeys():
+        print key
+
+    test2.get('g', 'foo')
+    #test2.get('b')
+    test2.get('b', 'bar')
+    test2.setdefault('b', 'blah')
+    print test1
+    print test2
+    print `test2`
+
+    print len(test2)
+
+    test3['a'] = [ 0, 1, 2, 3 ]
+
+    print test4