Added a try tag with except blocks. This tag is based on work by Jord…

…an B. Baker, and has been debugged and expanded to handle class-based exceptions.

DT_String.py

@@ -82,7 +82,7 @@
 # attributions are listed in the accompanying credits file.
 # 
 ##############################################################################
-"$Id: DT_String.py,v 1.25 1999/03/31 22:32:51 jim Exp $"
+"$Id: DT_String.py,v 1.26 1999/04/20 04:00:35 amos Exp $"
 
 from string import split, strip
 import regex, ts_regex
@@ -135,6 +135,7 @@ def parse_error(self, mess, tag, text, start):
         'else': ('else', 'DT_If','Else'),
         'comment': Comment,
         'raise': ('raise', 'DT_Raise','Raise'),
+        'try': ('try', 'DT_Try','Try'),
         }
 
     def SubTemplate(self, name): return String('', __name__=name)

DT_Try.py

@@ -0,0 +1,177 @@
+##############################################################################
+# 
+# Zope Public License (ZPL) Version 1.0
+# -------------------------------------
+# 
+# Copyright (c) Digital Creations.  All rights reserved.
+# 
+# This license has been certified as Open Source(tm).
+# 
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+# 
+# 1. Redistributions in source code must retain the above copyright
+#    notice, this list of conditions, and the following disclaimer.
+# 
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions, and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 
+# 3. Digital Creations requests that attribution be given to Zope
+#    in any manner possible. Zope includes a "Powered by Zope"
+#    button that is installed by default. While it is not a license
+#    violation to remove this button, it is requested that the
+#    attribution remain. A significant investment has been put
+#    into Zope, and this effort will continue if the Zope community
+#    continues to grow. This is one way to assure that growth.
+# 
+# 4. All advertising materials and documentation mentioning
+#    features derived from or use of this software must display
+#    the following acknowledgement:
+# 
+#      "This product includes software developed by Digital Creations
+#      for use in the Z Object Publishing Environment
+#      (http://www.zope.org/)."
+# 
+#    In the event that the product being advertised includes an
+#    intact Zope distribution (with copyright and license included)
+#    then this clause is waived.
+# 
+# 5. Names associated with Zope or Digital Creations must not be used to
+#    endorse or promote products derived from this software without
+#    prior written permission from Digital Creations.
+# 
+# 6. Modified redistributions of any form whatsoever must retain
+#    the following acknowledgment:
+# 
+#      "This product includes software developed by Digital Creations
+#      for use in the Z Object Publishing Environment
+#      (http://www.zope.org/)."
+# 
+#    Intact (re-)distributions of any official Zope release do not
+#    require an external acknowledgement.
+# 
+# 7. Modifications are encouraged but must be packaged separately as
+#    patches to official Zope releases.  Distributions that do not
+#    clearly separate the patches from the original work must be clearly
+#    labeled as unofficial distributions.  Modifications which do not
+#    carry the name Zope may be packaged in any form, as long as they
+#    conform to all of the clauses above.
+# 
+# 
+# Disclaimer
+# 
+#   THIS SOFTWARE IS PROVIDED BY DIGITAL CREATIONS ``AS IS'' AND ANY
+#   EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+#   PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL DIGITAL CREATIONS OR ITS
+#   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+#   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+#   USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+#   ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+#   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+#   OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+#   SUCH DAMAGE.
+# 
+# 
+# This software consists of contributions made by Digital Creations and
+# many individuals on behalf of Digital Creations.  Specific
+# attributions are listed in the accompanying credits file.
+# 
+##############################################################################
+
+import string, sys
+from DT_Util import parse_params, render_blocks, namespace, InstanceDict
+
+class Try:
+    """Zope DTML Exception handling
+    
+    usage:
+    
+    <!--#try-->
+    <!--#except SomeError AnotherError-->
+    <!--#except YetAnotherError-->
+    <!--#except-->
+    <!--#/try-->
+    
+    The DTML try tag functions quite like Python's try command. The main
+    difference is that DTML does not have a finally or an else construct.
+    
+    The contents of the try tag are rendered. If an exception is raised,
+    then control switches to the except blocks. The first except block to
+    match the type of the error raised is rendered. If an except block has
+    no name then it matches all raised errors.
+    
+    The try tag understands class-based exceptions, as well as string-based
+    exceptions. Note the raise tag raises string-based exceptions.
+    
+    Original version by Jordan B. Baker.
+    """
+
+    name = 'try'
+    blockContinuations = 'except',
+
+    def __init__(self, blocks):
+        tname, args, section = blocks[0]
+
+        self.args = parse_params(args)
+        self.section = section.blocks
+
+        # store handlers as tuples (name,block)
+        self.handlers = []
+
+        for tname,nargs,nsection in blocks[1:]:
+            for errname in string.split(nargs):
+                self.handlers.append((errname,nsection.blocks))
+            if string.strip(nargs)=='':
+                self.handlers.append(('',nsection.blocks))
+
+    def render(self, md):
+        # first we try to render the first block
+        try:
+            return render_blocks(self.section, md)
+        except:
+            # but an error occurs.. save the info.
+            einfo = sys.exc_info()
+            if type(einfo[0])==type(''):
+                errname = einfo[0]
+            else:
+                errname = einfo[0].__name__
+
+            handler = self.find_handler(einfo[0])
+
+            if handler is None:
+                # we didn't find a handler, so reraise the error
+                raise
+
+            # found the handler block, now render it
+            try:
+                ns = namespace(self, error_type=errname, error_message=einfo[1])[0]
+                md._push(InstanceDict(ns,md))
+                return render_blocks(handler, md)
+            finally:
+                md._pop(1)
+
+    def find_handler(self,exception):
+        "recursively search for a handler for a given exception"
+        if type(exception)==type(''):
+            for e,h in self.handlers:
+                if exception==e or e=='':
+                    return h
+            else:
+                return None
+        for e,h in self.handlers:
+            if e==exception.__name__ or e=='' or self.match_base(exception,e):
+                return h    
+        return None 
+
+    def match_base(self,exception,name):
+        for base in exception.__bases__:
+            if base.__name__==name or self.match_base(base,name):
+                return 1
+        return None
+
+    __call__ = render