[Checkins] SVN: Sandbox/malthe/chameleon.core/ Make default symbol available to dynamic attribute evaluations.

[Malthe Borch]

Log message for revision 93040:
  Make default symbol available to dynamic attribute evaluations.

Changed:
  U   Sandbox/malthe/chameleon.core/CHANGES.txt
  U   Sandbox/malthe/chameleon.core/src/chameleon/core/clauses.py
  U   Sandbox/malthe/chameleon.core/src/chameleon/core/config.py
  U   Sandbox/malthe/chameleon.core/src/chameleon/core/translation.py

-=-
Modified: Sandbox/malthe/chameleon.core/CHANGES.txt
===================================================================
--- Sandbox/malthe/chameleon.core/CHANGES.txt	2008-11-17 12:03:21 UTC (rev 93039)
+++ Sandbox/malthe/chameleon.core/CHANGES.txt	2008-11-17 12:03:43 UTC (rev 93040)
@@ -4,6 +4,9 @@
 HEAD
 ~~~~
 
+- Make `default` symbol available to dynamic attribute
+  evaluations. [malthe]
+
 - Visit evaluation before assignment in order to support assignments
   that rely on the same name in the dynamic variable scope. [malthe]
 

Modified: Sandbox/malthe/chameleon.core/src/chameleon/core/clauses.py
===================================================================
--- Sandbox/malthe/chameleon.core/src/chameleon/core/clauses.py	2008-11-17 12:03:21 UTC (rev 93039)
+++ Sandbox/malthe/chameleon.core/src/chameleon/core/clauses.py	2008-11-17 12:03:43 UTC (rev 93040)
@@ -488,6 +488,18 @@
     >>> _out.getvalue()
     '<div alt="Hello World!">Hello Universe!</div>'
 
+    Attribute default value is available under the `default` symbol.
+
+    >>> _out, _write, stream = testing.setup_stream('utf-8')
+    >>> tag = Tag('div', dict(alt=testing.pyexp('default')),
+    ...     defaults=dict(alt='Hello World!'))
+    >>> tag.begin(stream)
+    >>> stream.out('Hello Universe!')
+    >>> tag.end(stream)
+    >>> exec stream.getvalue()
+    >>> _out.getvalue()
+    '<div alt="Hello World!">Hello Universe!</div>'
+
     Verify that unicode data is handled correctly.
 
     >>> _out, _write, stream = testing.setup_stream()
@@ -531,9 +543,10 @@
     '<br />'
     """
 
-    def __init__(self, tag, attributes=None,
-                 selfclosing=False, expression=None, cdata=False):
+    def __init__(self, tag, attributes=None, selfclosing=False,
+                 expression=None, cdata=False, defaults={}):
         self.tag = tag.split('}')[-1]
+        self.defaults = defaults
         self.selfclosing = selfclosing
         self.attributes = attributes or {}
         self.expression = expression and Assign(expression)
@@ -592,9 +605,16 @@
             stream.outdent()
             
         for attribute, value in dynamic:
+            default = self.defaults.get(attribute)
+            if default is not None:
+                stream.write("%s = %s" % (stream.symbols.default, repr(default)))
+            
             assign = Assign(value)
             assign.begin(stream, temp)
 
+            if default is not None:
+                stream.write("%s = None" % stream.symbols.default)
+                
             # only include attribute if expression is not ``None`` or ``False``
             stream.write("if %s is not None and %s is not False:" % (temp, temp))
             stream.indent()

Modified: Sandbox/malthe/chameleon.core/src/chameleon/core/config.py
===================================================================
--- Sandbox/malthe/chameleon.core/src/chameleon/core/config.py	2008-11-17 12:03:21 UTC (rev 93039)
+++ Sandbox/malthe/chameleon.core/src/chameleon/core/config.py	2008-11-17 12:03:43 UTC (rev 93040)
@@ -57,7 +57,8 @@
     negotiate = '_negotiate'
     translate = '_translate'
     validate = '_validate'
-
+    default = 'default'
+    
     # advertised symbols
     repeat = 'repeat'
     language = 'target_language'

Modified: Sandbox/malthe/chameleon.core/src/chameleon/core/translation.py
===================================================================
--- Sandbox/malthe/chameleon.core/src/chameleon/core/translation.py	2008-11-17 12:03:21 UTC (rev 93039)
+++ Sandbox/malthe/chameleon.core/src/chameleon/core/translation.py	2008-11-17 12:03:43 UTC (rev 93040)
@@ -234,7 +234,7 @@
             tag = clauses.Tag(
                 self.element.tag, attributes,
                 expression=self.dict_attributes, selfclosing=selfclosing,
-                cdata=self.cdata is not None)
+                cdata=self.cdata is not None, defaults=self.static_attributes)
             if self.omit:
                 _.append(clauses.Condition(
                     self.omit, [tag], finalize=False, invert=True))