added some convenience methods to Jeep

git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@2109 fd906abe-77d9-0310-91a1-e0d9ade77398

util/jeep.py

@@ -31,6 +31,11 @@ class Jeep(object):
     _attributes = ('_sequence',)
 
     def __init__(self, seq=[]):
+        if isinstance(seq, Jeep):
+            self._sequence = list(seq.keys())
+            for key, value in seq.items():
+                object.__setattr__(self, key, value)
+        else:
             sequence = self._sequence = []
             for item in seq:
                 if isinstance(item, (list, tuple)) and len(item) == 2:
@@ -75,7 +80,7 @@ class Jeep(object):
         return getattr(self, key, _notfound) is not _notfound
 
     def keys(self):
-        return [key for key in self._sequence]
+        return list(self._sequence)
 
     def values(self):
         return list(self)
@@ -94,9 +99,6 @@ class Jeep(object):
             return value
         return existing
 
-    def index(self, key):
-        return self._sequence.index(key)
-
     def append(self, obj):
         self.insert(len(self), obj)
 
@@ -135,9 +137,25 @@ class Jeep(object):
     def index(self, obj):
         idx = self.find(obj)
         if idx < 0:
-            raise ValueError('list.index(x): x not in list')
+            raise ValueError('list.index(x): %r not in list' % obj)
         return idx
 
+    def remove(self, *keys):
+        myKeys = self.keys()
+        for key in keys:
+            if key in myKeys:
+                del self[key]
+
+    def select(self, *keys):
+        myKeys = self._sequence
+        self._sequence = [k for k in keys if k in myKeys]
+        for k in myKeys:
+            if k not in keys:
+                super(Jeep, self).__delattr__(k)
+
+    def reorder(self, delta, *keys):
+        self._sequence = moveByDelta(self._sequence, keys, delta)
+
 
 class Term(object):
     """ A simple name/title association that may be put in a jeep object.
@@ -152,3 +170,20 @@ class Term(object):
     def __str__(self):
         return self.title
 
+
+def moveByDelta(objs, toMove, delta):
+    """ Return the list given by objs re-ordered in a way that the elements
+        of toMove (which must be in the objs list) have been moved by delta.
+    """
+    result = [obj for obj in objs if obj not in toMove]
+    if delta < 0:
+        objs = list(reversed(objs))
+        result.reverse()
+    toMove = sorted(toMove, lambda x,y: cmp(objs.index(x), objs.index(y)))
+    for element in toMove:
+        newPos = min(len(result), objs.index(element) + abs(delta))
+        result.insert(newPos, element)
+    if delta < 0:
+        result.reverse()
+    return result
+

util/jeep.txt

@@ -78,6 +78,25 @@ More Dictionary Methods
   >>> dict(jeep)
   {'second': 'new second value', 'third': 'third value', 'first': 'first value'}
 
+  >>> jeep.setdefault('first', 'new first value')
+  'first value'
+  >>> jeep['first']
+  'first value'
+  >>> jeep.setdefault('fourth', 'new fourth value')
+  'new fourth value'
+  >>> jeep['fourth']
+  'new fourth value'
+  >>> len(jeep)
+  4
+
+  >>> del jeep['fourth']
+  >>> len(jeep)
+  3
+  >>> del jeep['fourth']
+  Traceback (most recent call last):
+  ...
+  ValueError: ...not in list
+
 More Methods and Operators
 --------------------------
 
@@ -103,7 +122,7 @@ Sequence Additions with Named Objects
 -------------------------------------
 
 Objects that have a ``__name__`` attribute can be appended
-to a Jeep object as the dictionary key can be obtained from these attribute.
+to a Jeep object as the dictionary key can be obtained from this attribute.
 
   >>> class Term(object):
   ...     def __init__(self, token, title=None, value=None):
@@ -135,7 +154,54 @@ an exception:
 Constructors
 ------------
 
-  >>> jeep2 = Jeep((('f', '1st'), ('s', '2nd'), ('t', '3rd')))
+A simple way of creating a Jeep object is using a sequence
+of key-value pairs.
+
+  >>> jeep2 = Jeep((('1', '1st'), ('2', '2nd'), ('3', '3rd')))
   >>> list(jeep2)
   ['1st', '2nd', '3rd']
 
+Using a Jeep object as the argument of the constructor yields a shallow
+copy.
+
+  >>> jeep3 = Jeep(jeep2)
+  >>> jeep3['1'] is jeep2['1']
+  True
+  >>> jeep3['4'] = '4th'
+  >>> len(jeep3)
+  4
+  >>> len(jeep2)
+  3
+
+More in-place changes
+---------------------
+
+Remove elements in a fault-tolerant way.
+
+  >>> jeep.keys()
+  ['first', 'term2', 'second', 'term1']
+  >>> jeep.remove('third', 'second')
+  >>> len(jeep)
+  3
+  >>> jeep.keys()
+  ['first', 'term2', 'term1']
+  >>> 'second' in jeep
+  False
+
+Reorder the sequence and remove all elements that are not
+in the argument list.
+
+  >>> jeep.select('term1', 'term2', 'nope')
+  >>> jeep.keys()
+  ['term1', 'term2']
+  >>> 'first' in jeep
+  False
+
+You may even reposition a certain element.
+
+  >>> jeep3.keys()
+  ['1', '2', '3', '4']
+  >>> jeep3.reorder(-1, '2', '4')
+  >>> jeep3.keys()
+  ['2', '1', '4', '3']
+