provide dynamic default value (via TAL expression)

git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@3721 fd906abe-77d9-0310-91a1-e0d9ade77398

composer/schema/README.txt

@@ -61,6 +61,13 @@ Field types
   >>> sorted(t.token for t in textFieldTypes)
   ['textarea', 'textline']
 
+Dynamic default values
+----------------------
+
+  >>> idField = Field(u'id', default='user/title|string:???', defaultValueType='tales')
+  >>> idField.getDefaultValue()
+  '???'
+
 
 Creating a schema from an interface
 ===================================
@@ -164,6 +171,7 @@ Create a new object using a schema-based form
   >>> form = CreateForm(container, TestRequest(form=input))
   >>> form.interface = IPerson
   >>> form.factory = Person
+
   >>> form.nextUrl = 'dummy_url'  # avoid hassle with IAbsoluteURL view...
   >>> form.getName = lambda x: x.lastName.lower()
 

composer/schema/field.py

@@ -31,6 +31,8 @@ from zope.component import adapts
 from zope import component
 from zope.i18n.format import DateTimeParseError
 from zope.i18n.locales import locales
+from zope.tales.engine import Engine
+from zope.tales.tales import Context
 
 from cybertools.composer.base import Component
 from cybertools.composer.schema.interfaces import IField, IFieldInstance
@@ -51,6 +53,8 @@ class Field(Component):
     renderFactory = None
     default = None
     default_method = None
+    defaultValueType = 'static'
+
     value_type = None
 
     fieldTypeInfo = None
@@ -84,11 +88,21 @@ class Field(Component):
     def getDefaultValue(self):
         if callable(self.default_method):
             return self.default_method()
+        if self.defaultValueType == 'tales':
+            expr = Engine.compile(self.default)
+            ctx = Context(Engine, self.getContextProperties())
+            return expr(ctx)
         return self.default
     def setDefaultValue(self, value):
         self.default = value
     defaultValue = property(getDefaultValue, setDefaultValue)
 
+    def getDefaultValueExpr(self):
+        return self.default
+    def setDefaultValueExpr(self, value):
+        self.default = value
+    defaultValueExpr = property(getDefaultValueExpr, setDefaultValueExpr)
+
     @property
     def fieldRenderer(self):
         return self.getFieldTypeInfo().fieldRenderer
@@ -129,6 +143,9 @@ class Field(Component):
         fi.clientInstance = clientInstance
         return fi
 
+    def getContextProperties(self):
+        return dict(context=self, user=None)
+
 
 class FieldInstance(object):
 
@@ -152,7 +169,7 @@ class FieldInstance(object):
             method = getattr(self.clientInstance.context, dm, None)
             if method:
                 return method()
-        return self.context.defaultValue
+        return self.context.getDefaultValue()
 
     def getRawValue(self, data, key, default=None):
         return data.get(key, default)

composer/schema/interfaces.py

@@ -133,7 +133,7 @@ standardFieldNames = SimpleVocabulary((
 ))
 
 defaultValueTypes = SimpleVocabulary((
-    SimpleTerm('string', 'string', 'String'),
+    SimpleTerm('static', 'static', 'Static data'),
     SimpleTerm('tales', 'tales', 'TAL expression'),
 ))
 
@@ -167,17 +167,17 @@ class IField(IComponent):
                 required=False,
                 default='',
                 vocabulary=standardFieldNames,)
-    defaultValue = schema.TextLine(
+    defaultValueExpr = schema.TextLine(
                 title=_(u'Default'),
                 description=_(u'Value with which to pre-set the field contents. '
                         'Use this also for populating a calculated field.'),
                 required=False,)
     defaultValueType = schema.Choice(
                 title=_(u'Default type'),
-                description=_(u'The type of the default, i.e. a fixed string '
+                description=_(u'The type of the default, i.e. a static value '
                         u'or an expression that is used to calculate the value.'),
                 required=False,
-                default='string',
+                default='static',
                 vocabulary=defaultValueTypes)
     required = schema.Bool(
                 title=_(u'Required'),

composer/schema/schema.py

@@ -52,6 +52,9 @@ class Schema(Template):
 
     @property
     def fields(self):
+        return self.getFields()
+
+    def getFields(self):
         return self.components
 
     @property