Changes between Version 4 and Version 5 of PyYAML

Timestamp:

04/17/06 14:18:15 (7 years ago)

Author:

xi

Comment:

Refrect recent changes.

PyYAML

@@ -113 +113 @@
 
 You may define constructors for your own application-specific tags. You may use
-either the function '''yaml.Constructor.add_constructor''' or subclass from
-'''yaml.YAMLObject'''.
-
-If you use '''yaml.YAMLObject''', you need to define the class attribute '''yaml_tag'''
-and the class methods '''from_yaml''', '''to_yaml''':
+either the function '''yaml.add_constructor''' or subclass from '''yaml.YAMLObject'''.
+
+Instances of '''yaml.YAMLObject''' are automatically serialized to YAML and vice versa.
+You only need to define the YAML tag with the '''yaml_tag''' variable.
 {{{
 #!python
 class Person(yaml.YAMLObject):
     yaml_tag = '!Person'
-    @classmethod
-    def from_yaml(cls, constructor, node):
-        # Convert the node to a dictionary
-        attributes = constructor.construct_mapping(node)
-        # Convert spaces into underlines
-        for key in attributes:
-            if ' ' in key:
-                value = attributes[key]
-                del attributes[key]
-                key = key.replace(' ', '_')
-                attributes[key] = value
-        # Create an object
-        return cls(**attributes)
-    @classmethod
-    def to_yaml(cls, representer, person):
-        # Create mapping node
-        mapping = {}
-        for attribute in person.__dict__:
-            key = attribute.replace('_', ' ')
-            value = getattr(person, attribute)
-            if value is not None:
-                mapping[key] = getattr(person, attribute)
-        return representer.represent_mapping(cls.yaml_tag, mapping)
     def __init__(self, first_name=None, last_name=None, email=None, birthday=None):
         self.first_name = first_name
@@ -150 +126 @@
         self.email = email
         self.birthday = birthday
-}}}
-
-After that, PyYAML 3000 will convert '''!Person'''-tagged nodes to '''Person''' objects and vice versa.
+    def __repr__(self):
+        return "%s(first_name=%r, last_name=%r, email=%r, birthday=%r)"  \
+                % (self.__class__.__name__, self.first_name, self.last_name,
+                        self.email, self.birthday)
+}}}
+
 {{{
 #!python
 >>> p = yaml.load("""
 ... !Person
-... first name: Kirill
-... last name: Simonov
+... first_name: Kirill
+... last_name: Simonov
 ... email: xi(at)resolvent.net
+... birthday: none
 ... """)
 >>> print p
-<__main__.Person object at 0xb7b5e44c>
->>> p.first_name, p.last_name, p.email, p.birthday
-('Kirill', 'Simonov', 'xi(at)resolvent.net', None)
+Person(first_name='Kirill', last_name='Simonov', email='xi(at)resolvent.net', birthday='none')
 >>> print yaml.dump(p)
 !Person
-first name: Kirill
-last name: Simonov
+last_name: Simonov
+first_name: Kirill
 email: xi(at)resolvent.net
+birthday: none
 }}}
 
@@ -180 +159 @@
 def represent_person(representer, person):
     # ...
-yaml.Constructor.add_constructor('!Person', construct_person)
-yaml.Representer.add_representer(Person, represent_person)
-}}}
-
-=== Loading all documents ===
+yaml.add_constructor('!Person', construct_person)
+yaml.add_representer(Person, represent_person)
+}}}
+
+=== Parsing and emitting multiple documents in a stream ===
 
 If an input stream contains several documents, you may load all of them using the '''yaml.load_all''' function.
@@ -221 +200 @@
 PyYAML 3000 provides low-level event-based and easy-to-use parser and emitter API.
 
-Parser example:
+Example:
 {{{
 #!python
@@ -239 +218 @@
 ... """
 >>> for event in yaml.parse(data): print event
-
 StreamStartEvent()
-
 DocumentStartEvent()
-ScalarEvent(anchor=None, tag=u'!tag', value=u'scalar')
+ScalarEvent(anchor=None, tag=u'!tag', implicit=(False, False), value=u'scalar')
 DocumentEndEvent()
-
 DocumentStartEvent()
-SequenceStartEvent(anchor=None, tag=None)
-ScalarEvent(anchor=u'anchor', tag=None, value=u'item')
-ScalarEvent(anchor=None, tag=None, value=u'another item')
+SequenceStartEvent(anchor=None, tag=None, implicit=True)
+ScalarEvent(anchor=u'anchor', tag=None, implicit=(True, False), value=u'item')
+ScalarEvent(anchor=None, tag=None, implicit=(True, False), value=u'another item')
 AliasEvent(anchor=u'anchor')
 SequenceEndEvent()
 DocumentEndEvent()
-
 DocumentStartEvent()
-MappingStartEvent(anchor=None, tag=None)
-ScalarEvent(anchor=None, tag=None, value=u'key')
-ScalarEvent(anchor=None, tag=None, value=u'value')
-SequenceStartEvent(anchor=None, tag=None)
-ScalarEvent(anchor=None, tag=None, value=u'complex')
-ScalarEvent(anchor=None, tag=None, value=u'key')
+MappingStartEvent(anchor=None, tag=None, implicit=True)
+ScalarEvent(anchor=None, tag=None, implicit=(True, False), value=u'key')
+ScalarEvent(anchor=None, tag=None, implicit=(True, False), value=u'value')
+SequenceStartEvent(anchor=None, tag=None, implicit=True)
+ScalarEvent(anchor=None, tag=None, implicit=(True, False), value=u'complex')
+ScalarEvent(anchor=None, tag=None, implicit=(True, False), value=u'key')
 SequenceEndEvent()
-SequenceStartEvent(anchor=None, tag=None)
-ScalarEvent(anchor=None, tag=None, value=u'complex')
-ScalarEvent(anchor=None, tag=None, value=u'value')
+SequenceStartEvent(anchor=None, tag=None, implicit=True)
+ScalarEvent(anchor=None, tag=None, implicit=(True, False), value=u'complex')
+ScalarEvent(anchor=None, tag=None, implicit=(True, False), value=u'value')
 SequenceEndEvent()
 MappingEndEvent()
 DocumentEndEvent()
-
 StreamEndEvent()
-
 >>> events = [
 ... yaml.StreamStartEvent(encoding='utf-8'),
 ... yaml.DocumentStartEvent(explicit=True),
-... yaml.MappingStartEvent(anchor=None, tag=None),
-... yaml.ScalarEvent(anchor=None, tag=None, value=u'flow sequence', implicit=True),
-... yaml.SequenceStartEvent(anchor=None, tag=None, flow_style=True),
-... yaml.ScalarEvent(anchor=None, tag=None, value=u'123', implicit=True),
-... yaml.ScalarEvent(anchor=None, tag=None, value=u'456', implicit=True),
+... yaml.MappingStartEvent(anchor=None, tag=None, implicit=True),
+... yaml.ScalarEvent(anchor=None, tag=None, value=u'flow sequence', implicit=(True, True)),
+... yaml.SequenceStartEvent(anchor=None, tag=None, flow_style=True, implicit=True),
+... yaml.ScalarEvent(anchor=None, tag=None, value=u'123', implicit=(True, False)),
+... yaml.ScalarEvent(anchor=None, tag=None, value=u'456', implicit=(True, False)),
 ... yaml.SequenceEndEvent(),
-... yaml.ScalarEvent(anchor=None, tag=None, value=u'block scalar', implicit=True),
-... yaml.ScalarEvent(anchor=None, tag=None, value=u'YAML\nis\nfun!\n', style='|'),
+... yaml.ScalarEvent(anchor=None, tag=None, value=u'block scalar', implicit=(True, True)),
+... yaml.ScalarEvent(anchor=None, tag=None, value=u'YAML\nis\nfun!\n', style='|', implicit=(True, True)),
 ... yaml.MappingEndEvent(),
 ... yaml.DocumentEndEvent(explicit=True),