Order state elements to generate more readable YAML.
[python-bulletml.git] / bulletml / parser.py
index 2ad648c..51e15ad 100644 (file)
@@ -24,6 +24,7 @@ except ImportError:
 from bulletml.errors import Error
 from bulletml.expr import NumberDef, INumberDef
 
+
 __all_ = ["ParseError", "BulletML"]
 
 class ParseError(Error):
@@ -44,7 +45,7 @@ class ParamList(object):
         self.params = list(params)
 
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         return cls([NumberDef(subelem.text) for subelem in element
                     if realtag(subelem) == "param"])
@@ -66,8 +67,15 @@ class Direction(object):
         self.type = type
         self.value = value
 
+    def __getstate__(self):
+        return [('type', self.type), ('value', self.value.expr)]
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(state["type"], NumberDef(state["value"]))
+
     @classmethod
-    def FromElement(cls, doc, element, default="absolute"):
+    def FromXML(cls, doc, element, default="absolute"):
         """Construct using an ElementTree-style element."""
         return cls(element.get("type", default), NumberDef(element.text))
 
@@ -85,13 +93,23 @@ class ChangeDirection(object):
         self.term = term
         self.direction = direction
 
+    def __getstate__(self):
+        return [('frames', self.term.expr),
+                ('type', self.direction.type),
+                ('value', self.direction.value.expr)]
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(INumberDef(state["frames"]),
+                      Direction(state["type"], NumberDef(state["value"])))
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         for subelem in element.getchildren():
             tag = realtag(subelem)
             if tag == "direction":
-                direction = Direction.FromElement(doc, subelem)
+                direction = Direction.FromXML(doc, subelem)
             elif tag == "term":
                 term = INumberDef(subelem.text)
         try:
@@ -117,8 +135,15 @@ class Speed(object):
         self.type = type
         self.value = value
 
+    def __getstate__(self):
+        return [('type', self.type), ('value', self.value.expr)]
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(state["type"], NumberDef(state["value"]))
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         return cls(element.get("type", "absolute"), NumberDef(element.text))
 
@@ -135,13 +160,23 @@ class ChangeSpeed(object):
         self.term = term
         self.speed = speed
 
+    def __getstate__(self):
+        return [('frames', self.term.expr),
+                ('type', self.speed.type),
+                ('value', self.speed.value.expr)]
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(INumberDef(state["frames"]),
+                      Speed(state["type"], NumberDef(state["value"])))
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         for subelem in element.getchildren():
             tag = realtag(subelem)
             if tag == "speed":
-                speed = Speed.FromElement(doc, subelem)
+                speed = Speed.FromXML(doc, subelem)
             elif tag == "term":
                 term = INumberDef(subelem.text)
         try:
@@ -162,8 +197,14 @@ class Wait(object):
     def __init__(self, frames):
         self.frames = frames
 
+    def __getstate__(self):
+        return dict(frames=self.frames.expr)
+
+    def __setstate__(self, state):
+        self.__init__(INumberDef(state["frames"]))
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         return cls(INumberDef(element.text))
 
@@ -179,8 +220,14 @@ class Tag(object):
     def __init__(self, tag):
         self.tag = tag
 
+    def __getstate__(self):
+        return dict(tag=self.tag)
+
+    def __setstate__(self, state):
+        self.__init__(state["tag"])
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         return cls(element.text)
 
@@ -189,9 +236,15 @@ class Untag(object):
 
     def __init__(self, tag):
         self.tag = tag
+        
+    def __getstate__(self):
+        return dict(tag=self.tag)
+
+    def __setstate__(self, state):
+        self.__init__(state["tag"])
 
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         return cls(element.text)
 
@@ -202,7 +255,7 @@ class Vanish(object):
         pass
 
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         return cls()
 
@@ -215,18 +268,25 @@ class Repeat(object):
     def __init__(self, times, action):
         self.times = times
         self.action = action
+
+    def __getstate__(self):
+        return [('times', self.times.expr), ('action', self.action)]
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(INumberDef(state["times"]), state["action"])
     
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         for subelem in element.getchildren():
             tag = realtag(subelem)
             if tag == "times":
                 times = INumberDef(subelem.text)
             elif tag == "action":
-                action = ActionDef.FromElement(doc, subelem)
+                action = ActionDef.FromXML(doc, subelem)
             elif tag == "actionRef":
-                action = ActionRef.FromElement(doc, subelem)
+                action = ActionRef.FromXML(doc, subelem)
         try:
             return cls(times, action)
         except UnboundLocalError as exc:
@@ -249,8 +309,21 @@ class Accel(object):
         self.horizontal = horizontal
         self.vertical = vertical
 
+    def __getstate__(self):
+        state = [('frames', self.term.expr)]
+        if self.horizontal:
+            state.append(('horizontal', self.horizontal))
+        if self.vertical:
+            state.append(('vertical', self.vertical))
+        return state
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(INumberDef(state["frames"]), state.get("horizontal"),
+                      state.get("vertical"))
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         horizontal = None
         vertical = None
@@ -260,9 +333,9 @@ class Accel(object):
             if tag == "term":
                 term = INumberDef(subelem.text)
             elif tag == "horizontal":
-                horizontal = Speed.FromElement(doc, subelem)
+                horizontal = Speed.FromXML(doc, subelem)
             elif tag == "vertical":
-                vertical = Speed.FromElement(doc, subelem)
+                vertical = Speed.FromXML(doc, subelem)
 
         try:
             return cls(term, horizontal, vertical)
@@ -290,8 +363,22 @@ class BulletDef(object):
         self.speed = speed
         self.actions = list(actions)
 
+    def __getstate__(self):
+        state = []
+        if self.direction:
+            state.append(("direction", self.direction))
+        if self.speed:
+            state.append(("speed", self.speed))
+        if self.actions:
+            state.append(("actions", self.actions))
+        return state
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(**state)
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         actions = []
         speed = None
@@ -299,13 +386,13 @@ class BulletDef(object):
         for subelem in element.getchildren():
             tag = realtag(subelem)
             if tag == "direction":
-                direction = Direction.FromElement(doc, subelem)
+                direction = Direction.FromXML(doc, subelem)
             elif tag == "speed":
-                speed = Speed.FromElement(doc, subelem)
+                speed = Speed.FromXML(doc, subelem)
             elif tag == "action":
-                actions.append(ActionDef.FromElement(doc, subelem))
+                actions.append(ActionDef.FromXML(doc, subelem))
             elif tag == "actionRef":
-                actions.append(ActionRef.FromElement(doc, subelem))
+                actions.append(ActionRef.FromXML(doc, subelem))
         dfn = cls(actions, direction, speed)
         doc.bullets[element.get("label")] = dfn
         return dfn
@@ -326,12 +413,26 @@ class BulletRef(object):
 
     def __init__(self, bullet, params=None):
         self.bullet = bullet
-        self.params = params or ParamList()
+        self.params = ParamList() if params is None else params
+
+    def __getstate__(self):
+        state = []
+        if self.params.params:
+            params = [param.expr for param in self.params.params]
+            state.append(("params", params))
+        state.append(('bullet', self.bullet))
+        return state
+
+    def __setstate__(self, state):
+        state = dict(state)
+        bullet = state["bullet"]
+        params = [NumberDef(param) for param in state.get("params", [])]
+        self.__init__(bullet, ParamList(params))
 
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
-        bullet = cls(element.get("label"), ParamList.FromElement(doc, element))
+        bullet = cls(element.get("label"), ParamList.FromXML(doc, element))
         doc._bullet_refs.append(bullet)
         return bullet
 
@@ -347,7 +448,7 @@ class ActionDef(object):
 
     To support parsing new actions, add tags to
     ActionDef.CONSTRUCTORS. It maps tag names to classes with a
-    FromElement classmethod, which take the BulletML instance and
+    FromXML classmethod, which take the BulletML instance and
     ElementTree element as arguments.
     """
 
@@ -357,8 +458,15 @@ class ActionDef(object):
     def __init__(self, actions):
         self.actions = list(actions)
 
+    def __getstate__(self):
+        return dict(actions=self.actions)
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(state["actions"])
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         actions = []
         for subelem in element.getchildren():
@@ -368,7 +476,7 @@ class ActionDef(object):
             except KeyError:
                 continue
             else:
-                actions.append(ctr.FromElement(doc, subelem))
+                actions.append(ctr.FromXML(doc, subelem))
         dfn = cls(actions)
         doc.actions[element.get("label")] = dfn
         return dfn
@@ -386,10 +494,24 @@ class ActionRef(object):
         self.action = action
         self.params = params or ParamList()
 
+    def __getstate__(self):
+        state = []
+        if self.params.params:
+            params = [param.expr for param in self.params.params]
+            state.append(("params", params))
+        state.append(('action', self.action))
+        return state
+
+    def __setstate__(self, state):
+        state = dict(state)
+        action = state["action"]
+        params = [NumberDef(param) for param in state.get("params", [])]
+        self.__init__(action, ParamList(params))
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
-        action = cls(element.get("label"), ParamList.FromElement(doc, element))
+        action = cls(element.get("label"), ParamList.FromXML(doc, element))
         doc._action_refs.append(action)
         return action
 
@@ -412,8 +534,20 @@ class Offset(object):
         self.x = x
         self.y = y
 
+    def __getstate__(self):
+        state = [('type', self.type)]
+        if self.x:
+            state.append(('x', self.x.expr))
+        if self.y:
+            state.append(('y', self.y.expr))
+        return state
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(state["type"], state.get("x"), state.get("y"))
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         type = element.get("type", "relative")
         x = None
@@ -439,8 +573,32 @@ class FireDef(object):
         self.speed = speed
         self.offset = offset
 
+    def __getstate__(self):
+        state = []
+        if self.direction:
+            state.append(("direction", self.direction))
+        if self.speed:
+            state.append(("speed", self.speed))
+        if self.offset:
+            state.append(("offset", self.offset))
+        try:
+            params = self.bullet.params
+        except AttributeError:
+            state = dict(bullet=self.bullet)
+        else:
+            if params.params:
+                state.append(('bullet', self.bullet))
+            else:
+                # Strip out empty BulletRefs.
+                state.append(('bullet', self.bullet.bullet))
+        return state
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(**state)
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
         direction = None
         speed = None
@@ -449,15 +607,15 @@ class FireDef(object):
         for subelem in element.getchildren():
             tag = realtag(subelem)
             if tag == "direction":
-                direction = Direction.FromElement(doc, subelem, "aim")
+                direction = Direction.FromXML(doc, subelem, "aim")
             elif tag == "speed":
-                speed = Speed.FromElement(doc, subelem)
+                speed = Speed.FromXML(doc, subelem)
             elif tag == "bullet":
-                bullet = BulletDef.FromElement(doc, subelem)
+                bullet = BulletDef.FromXML(doc, subelem)
             elif tag == "bulletRef":
-                bullet = BulletRef.FromElement(doc, subelem)
+                bullet = BulletRef.FromXML(doc, subelem)
             elif tag == "offset":
-                offset = Offset.FromElement(doc, subelem)
+                offset = Offset.FromXML(doc, subelem)
         try:
             fire = cls(bullet, direction, speed, offset)
         except UnboundLocalError as exc:
@@ -485,10 +643,24 @@ class FireRef(object):
         self.fire = fire
         self.params = params or ParamList()
 
+    def __getstate__(self):
+        state = []
+        if self.params.params:
+            params = [param.expr for param in self.params.params]
+            state.append(("params", params))
+        state.append(('fire', self.fire))
+        return state
+
+    def __setstate__(self, state):
+        state = dict(state)
+        fire = state["fire"]
+        params = [NumberDef(param) for param in state.get("params", [])]
+        self.__init__(fire, ParamList(params))
+
     @classmethod
-    def FromElement(cls, doc, element):
+    def FromXML(cls, doc, element):
         """Construct using an ElementTree-style element."""
-        fired = cls(element.get("label"), ParamList.FromElement(doc, element))
+        fired = cls(element.get("label"), ParamList.FromXML(doc, element))
         doc._fire_refs.append(fired)
         return fired
 
@@ -506,7 +678,7 @@ class BulletML(object):
     firings, as well as a base game type.
 
     You can add tags to the BulletML.CONSTRUCTORS dictionary to extend
-    its parsing. It maps tag names to classes with a FromElement
+    its parsing. It maps tag names to classes with a FromXML
     classmethod, which take the BulletML instance and ElementTree
     element as arguments.
     
@@ -524,9 +696,16 @@ class BulletML(object):
         self.actions = {} if actions is None else actions
         self.fires = {} if fires is None else fires
 
+    def __getstate__(self):
+        return [('type', self.type), ('actions', self.actions)]
+
+    def __setstate__(self, state):
+        state = dict(state)
+        self.__init__(state["type"], actions=state.get("actions"))
+
     @classmethod
-    def FromDocument(cls, source):
-        """Return a BulletML instance based on a string or file-like."""
+    def FromXML(cls, source):
+        """Return a BulletML instance based on XML."""
         if not hasattr(source, 'read'):
             source = StringIO(source)
 
@@ -542,7 +721,7 @@ class BulletML(object):
         for element in root.getchildren():
             tag = realtag(element)
             if tag in self.CONSTRUCTORS:
-                self.CONSTRUCTORS[tag].FromElement(self, element)
+                self.CONSTRUCTORS[tag].FromXML(self, element)
 
         try:
             for ref in self._bullet_refs:
@@ -564,6 +743,39 @@ class BulletML(object):
 
         return self
 
+    @classmethod
+    def FromYAML(cls, source):
+        """Create a BulletML instance based on YAML."""
+
+        # Late import to avoid a circular dependency.
+        try:
+            import bulletml.bulletyaml
+            import yaml
+        except ImportError:
+            raise ParseError("PyYAML is not available")
+        else:
+            try:
+                return yaml.load(source)
+            except Exception, exc:
+                raise ParseError(str(exc))
+
+    @classmethod
+    def FromDocument(cls, source):
+        """Create a BulletML instance based on a seekable file or string.
+
+        This attempts to autodetect if the stream is XML or YAML.
+        """
+        if not hasattr(source, 'read'):
+            source = StringIO(source)
+        start = source.read(1)
+        source.seek(0)
+        if start == "<":
+            return cls.FromXML(source)
+        elif start == "!" or start == "#":
+            return cls.FromYAML(source)
+        else:
+            raise ParseError("unknown initial character %r" % start)
+
     @property
     def top(self):
         """Get a list of all top-level actions."""