[pod] Added the possibility to define several variables, in 'with' statements, separated by ';'.

pod/actions.py

@@ -53,28 +53,38 @@ class BufferAction:
         # We store the result of evaluation of expr and fromExpr
         self.exprResult = None
         self.fromExprResult = None
+
     def writeError(self, errorMessage, dumpTb=True):
         # Empty the buffer
         self.buffer.__init__(self.buffer.env, self.buffer.parent)
         PodError.dump(self.buffer, errorMessage, withinElement=self.elem,
                       dumpTb=dumpTb)
         self.buffer.evaluate()
+
+    def evaluateExpression(self, expr):
+        '''Evaluates expression p_expr with the current context. Returns a tuple
+           (result, errorOccurred).'''
+        try:
+            res = eval(expr, self.buffer.env.context)
+            error = False
+        except:
+            res = None
+            self.writeError(EVAL_ERROR % expr)
+            error = True
+        return res, error
+
     def execute(self):
         # Check that if minus is set, we have an element which can accept it
         if self.minus and isinstance(self.elem, Table) and \
            (not self.elem.tableInfo.isOneCell()):
             self.writeError(TABLE_NOT_ONE_CELL % self.expr)
         else:
-            errorOccurred = False
+            error = False
             if self.expr:
-                try:
+                self.exprResult, error = self.evaluateExpression(self.expr)
-                    self.exprResult = eval(self.expr, self.buffer.env.context)
+            if not error:
-                except:
-                    self.exprResult = None
-                    self.writeError(EVAL_ERROR % self.expr)
-                    errorOccurred = True
-            if not errorOccurred:
                 self.do()
+
     def evaluateBuffer(self):
         if self.source == 'buffer':
             self.buffer.evaluate(removeMainElems = self.minus)
@@ -243,27 +253,48 @@ class NullAction(BufferAction):
     def do(self):
         self.evaluateBuffer()
 
-class VariableAction(BufferAction):
+class VariablesAction(BufferAction):
-    '''Action that allows to define a variable somewhere in the template.'''
+    '''Action that allows to define a set of variables somewhere in the
-    def __init__(self, name, buffer, expr, elem, minus, varName, source,
+       template.'''
-        fromExpr):
+    def __init__(self, name, buffer, elem, minus, variables, source, fromExpr):
-        BufferAction.__init__(self, name, buffer, expr, elem, minus, source,
+        # We do not use the default Buffer.expr attribute for storing the Python
+        # expression, because here we will have several expressions, one for
+        # every defined variable.
+        BufferAction.__init__(self, name, buffer, None, elem, minus, source,
                               fromExpr)
-        self.varName = varName # Name of the variable
+        # Definitions of variables: ~{s_name: s_expr}~
+        self.variables = variables
+        # Results of executing the variables: ~{s_name: exprResult}~
+        self.results = {}
+
     def do(self):
         context = self.buffer.env.context
-        # Remember the variable hidden by our variable definition, if any
+        # Evaluate the variables' expressions: because there are several
-        hasHiddenVariable = False
+        # expressions, we did not use the standard, single-expression-minded
-        if context.has_key(self.varName):
+        # BufferAction code for evaluating the expression.
-            hiddenVariable = context[self.varName]
+        # Also: remember the names and values of the variables that we will hide
-            hasHiddenVariable = True
+        # in the context: after execution of this buffer we will restore those
-        # Add the variable to the context
+        # values in the context.
-        context[self.varName] = self.exprResult
+        hidden = None
+        for name, expr in self.variables.iteritems():
+            # Evaluate the expression
+            result, error = self.evaluateExpression(expr)
+            if error: return
+            self.results[name] = result
+            # Remember the variable previous value if already in the context
+            if name in context:
+                if not hidden:
+                    hidden = {name: context[name]}
+                else:
+                    hidden[name] = context[name]
+        # Add our variables to the context
+        context.update(self.results)
         # Evaluate the buffer
         self.evaluateBuffer()
-        # Restore hidden variable if any
+        # Restore hidden variables if any
-        if hasHiddenVariable:
+        if hidden: context.update(hidden)
-            context[self.varName] = hiddenVariable
+        # Delete not-hidden variables
-        else:
+        for name in self.variables.iterkeys():
-            del context[self.varName]
+            if hidden and (name in hidden): continue
+            del context[name]
 # ------------------------------------------------------------------------------

pod/buffers.py

@@ -23,7 +23,7 @@ from xml.sax.saxutils import quoteattr
 from appy.shared.xml_parser import xmlPrologue, escapeXml
 from appy.pod import PodError
 from appy.pod.elements import *
-from appy.pod.actions import IfAction, ElseAction, ForAction, VariableAction, \
+from appy.pod.actions import IfAction, ElseAction, ForAction, VariablesAction, \
                              NullAction
 
 # ------------------------------------------------------------------------------
@@ -359,6 +359,18 @@ class MemoryBuffer(Buffer):
         self.content += u' '
         return attrs
 
+    def _getVariables(self, expr):
+        '''Returns variable definitions in p_expr as a dict
+           ~{s_varName: s_expr}~.'''
+        exprs = expr.strip().split(';')
+        res = {}
+        for sub in exprs:
+            varRes = MemoryBuffer.varRex.match(sub)
+            if not varRes:
+                raise ParsingError(BAD_VAR_EXPRESSION % sub)
+            res[varRes.group(1)] = varRes.group(2)
+        return res
+
     def createAction(self, statementGroup):
         '''Tries to create an action based on p_statementGroup. If the statement
            is not correct, r_ is -1. Else, r_ is the index of the element within
@@ -432,12 +444,9 @@ class MemoryBuffer(Buffer):
                 self.action = ForAction(statementName, self, subExpr, podElem,
                                         minus, iter, source, fromClause)
             elif actionType == 'with':
-                varRes = MemoryBuffer.varRex.match(subExpr.strip())
+                variables = self._getVariables(subExpr)
-                if not varRes:
+                self.action = VariablesAction(statementName, self, podElem,
-                    raise ParsingError(BAD_VAR_EXPRESSION % subExpr)
+                                           minus, variables, source, fromClause)
-                varName, subExpr = varRes.groups()
-                self.action = VariableAction(statementName, self, subExpr,
-                    podElem, minus, varName, source, fromClause)
             else: # null action
                 if not fromClause:
                     raise ParsingError(NULL_ACTION_ERROR)
@@ -460,6 +469,10 @@ class MemoryBuffer(Buffer):
         elif actionType == 'if':
             self.action = IfAction('if', self, statement, elem, False,
                                    'buffer', None)
+        elif actionType == 'var':
+            variables = self._getVariables(statement)
+            self.action = VariablesAction('var', self, elem, False, variables,
+                                          'buffer', None)
         return res
 
     def cut(self, index, keepFirstPart):

px/__init__.py

@@ -3,9 +3,7 @@
    Python and XML.'''
 
 # ------------------------------------------------------------------------------
-from UserDict import UserDict
 from px_parser import PxParser, PxEnvironment
-from appy.pod.renderer import BAD_CONTEXT
 
 # Exception class --------------------------------------------------------------
 class PxError(Exception): pass
@@ -37,16 +35,8 @@ class Px:
         self.parser.parse(self.content)
 
     def __call__(self, context):
-        # Get the context in a standardized form.
+        # p_context must be a dict. Store it in the PX environment.
-        evalContext = {}
+        self.parser.env.context = context
-        if hasattr(context, '__dict__'):
-            evalContext.update(context.__dict__)
-        elif isinstance(context, dict) or isinstance(context, UserDict):
-            evalContext.update(context)
-        else:
-            raise PxError(BAD_CONTEXT)
-        # Store the context on the PX environment
-        self.parser.env.context = evalContext
         # Render the PX result and return it
         env = self.parser.env
         env.ast.evaluate()

px/px_parser.py

@@ -56,6 +56,8 @@ class PxEnvironment(XmlEnvironment):
 class PxParser(XmlParser):
     '''PX parser that is specific for parsing PX data.'''
 
+    pxAttributes = ('var', 'for', 'if')
+
     def __init__(self, env, caller=None):
         XmlParser.__init__(self, env, caller)
 
@@ -63,14 +65,14 @@ class PxParser(XmlParser):
         '''A start p_elem with p_attrs is encountered in the PX.'''
         e = self.env
         self.currentElem = elem
-        if attrs.has_key('for'):
+        # See if we have a PX attribute among p_attrs.
+        for name in self.pxAttributes:
+            if attrs.has_key(name):
                 # Dump the element in a new sub-buffer
                 e.addSubBuffer()
                 # Create the action for this buffer
-            e.currentBuffer.createPxAction(elem, 'for', attrs['for'])
+                e.currentBuffer.createPxAction(elem, name, attrs[name])
-        elif attrs.has_key('if'):
+                break
-            e.addSubBuffer()
-            e.currentBuffer.createPxAction(elem, 'if', attrs['if'])
         if e.isActionElem(elem):
             # Add a temp element in the buffer (that will be unreferenced
             # later). This way, when encountering the corresponding end element,