--- a/markup/input.py
+++ b/markup/input.py
@@ -24,12 +24,24 @@
 from markup.core import Attributes, Markup, QName, Stream
 
 
+class ParseError(Exception):
+    """Exception raised when fatal syntax errors are found in the input being
+    parsed."""
+
+    def __init__(self, message, filename='<string>', lineno=-1, offset=-1):
+        Exception.__init__(self, message)
+        self.filename = filename
+        self.lineno = lineno
+        self.offset = offset
+
+
 class XMLParser(object):
     """Generator-based XML parser based on roughly equivalent code in
     Kid/ElementTree."""
 
-    def __init__(self, source):
+    def __init__(self, source, filename=None):
         self.source = source
+        self.filename = filename
 
         # Setup the Expat parser
         parser = expat.ParserCreate('utf-8', '}')
@@ -48,73 +60,80 @@
 
         # Location reporting is only support in Python >= 2.4
         if not hasattr(parser, 'CurrentLineNumber'):
-            self.getpos = self._getpos_unknown
+            self._getpos = self._getpos_unknown
 
         self.expat = parser
-        self.queue = []
+        self._queue = []
 
     def __iter__(self):
-        bufsize = 4 * 1024 # 4K
-        done = False
-        while True:
-            while not done and len(self.queue) == 0:
-                data = self.source.read(bufsize)
-                if data == '': # end of data
-                    if hasattr(self, 'expat'):
-                        self.expat.Parse('', True)
-                        del self.expat # get rid of circular references
-                    done = True
-                else:
-                    self.expat.Parse(data, False)
-            for event in self.queue:
-                yield event
-            self.queue = []
-            if done:
-                break
+        try:
+            bufsize = 4 * 1024 # 4K
+            done = False
+            while True:
+                while not done and len(self._queue) == 0:
+                    data = self.source.read(bufsize)
+                    if data == '': # end of data
+                        if hasattr(self, 'expat'):
+                            self.expat.Parse('', True)
+                            del self.expat # get rid of circular references
+                        done = True
+                    else:
+                        self.expat.Parse(data, False)
+                for event in self._queue:
+                    yield event
+                self._queue = []
+                if done:
+                    break
+        except expat.ExpatError, e:
+            msg = str(e)
+            if self.filename:
+                msg += ', in ' + self.filename
+            raise ParseError(msg, self.filename, e.lineno, e.offset)
 
     def _getpos_unknown(self):
-        return (-1, -1)
+        return (self.filename or '<string>', -1, -1)
 
-    def getpos(self):
-        return self.expat.CurrentLineNumber, self.expat.CurrentColumnNumber
+    def _getpos(self):
+        return (self.filename or '<string>', self.expat.CurrentLineNumber,
+                self.expat.CurrentColumnNumber)
 
     def _handle_start(self, tag, attrib):
-        self.queue.append((Stream.START, (QName(tag), Attributes(attrib.items())),
-                           self.getpos()))
+        self._queue.append((Stream.START, (QName(tag), Attributes(attrib.items())),
+                           self._getpos()))
 
     def _handle_end(self, tag):
-        self.queue.append((Stream.END, QName(tag), self.getpos()))
+        self._queue.append((Stream.END, QName(tag), self._getpos()))
 
     def _handle_data(self, text):
-        self.queue.append((Stream.TEXT, text, self.getpos()))
+        self._queue.append((Stream.TEXT, text, self._getpos()))
 
     def _handle_prolog(self, version, encoding, standalone):
-        self.queue.append((Stream.PROLOG, (version, encoding, standalone),
-                           self.getpos()))
+        self._queue.append((Stream.PROLOG, (version, encoding, standalone),
+                           self._getpos()))
 
     def _handle_doctype(self, name, sysid, pubid, has_internal_subset):
-        self.queue.append((Stream.DOCTYPE, (name, pubid, sysid), self.getpos()))
+        self._queue.append((Stream.DOCTYPE, (name, pubid, sysid), self._getpos()))
 
     def _handle_start_ns(self, prefix, uri):
-        self.queue.append((Stream.START_NS, (prefix or '', uri), self.getpos()))
+        self._queue.append((Stream.START_NS, (prefix or '', uri), self._getpos()))
 
     def _handle_end_ns(self, prefix):
-        self.queue.append((Stream.END_NS, prefix or '', self.getpos()))
+        self._queue.append((Stream.END_NS, prefix or '', self._getpos()))
 
     def _handle_pi(self, target, data):
-        self.queue.append((Stream.PI, (target, data), self.getpos()))
+        self._queue.append((Stream.PI, (target, data), self._getpos()))
 
     def _handle_comment(self, text):
-        self.queue.append((Stream.COMMENT, text, self.getpos()))
+        self._queue.append((Stream.COMMENT, text, self._getpos()))
 
     def _handle_other(self, text):
         if text.startswith('&'):
             # deal with undefined entities
             try:
                 text = unichr(htmlentitydefs.name2codepoint[text[1:-1]])
-                self.queue.append((Stream.TEXT, text, self.getpos()))
+                self._queue.append((Stream.TEXT, text, self._getpos()))
             except KeyError:
-                lineno, offset = self.getpos()
+                lineno, offset = self._getpos()
                 raise expat.error("undefined entity %s: line %d, column %d" %
                                   (text, lineno, offset))
 
@@ -123,7 +142,7 @@
     return Stream(list(XMLParser(StringIO(text))))
 
 
-class HTMLParser(html.HTMLParser):
+class HTMLParser(html.HTMLParser, object):
     """Parser for HTML input based on the Python `HTMLParser` module.
     
     This class provides the same interface for generating stream events as
@@ -134,68 +153,79 @@
                               'hr', 'img', 'input', 'isindex', 'link', 'meta',
                               'param'])
 
-    def __init__(self, source):
+    def __init__(self, source, filename=None):
         html.HTMLParser.__init__(self)
         self.source = source
-        self.queue = []
+        self.filename = filename
+        self._queue = []
         self._open_tags = []
 
     def __iter__(self):
-        bufsize = 4 * 1024 # 4K
-        done = False
-        while True:
-            while not done and len(self.queue) == 0:
-                data = self.source.read(bufsize)
-                if data == '': # end of data
-                    self.close()
-                    done = True
-                else:
-                    self.feed(data)
-            for kind, data, pos in self.queue:
-                yield kind, data, pos
-            self.queue = []
-            if done:
-                open_tags = self._open_tags
-                open_tags.reverse()
-                for tag in open_tags:
-                    yield Stream.END, QName(tag), pos
-                break
+        try:
+            bufsize = 4 * 1024 # 4K
+            done = False
+            while True:
+                while not done and len(self._queue) == 0:
+                    data = self.source.read(bufsize)
+                    if data == '': # end of data
+                        self.close()
+                        done = True
+                    else:
+                        self.feed(data)
+                for kind, data, pos in self._queue:
+                    yield kind, data, pos
+                self._queue = []
+                if done:
+                    open_tags = self._open_tags
+                    open_tags.reverse()
+                    for tag in open_tags:
+                        yield Stream.END, QName(tag), pos
+                    break
+        except html.HTMLParseError, e:
+            msg = '%s: line %d, column %d' % (e.msg, e.lineno, e.offset)
+            if self.filename:
+                msg += ', in %s' % self.filename
+            raise ParseError(msg, self.filename, e.lineno, e.offset)
+
+    def _getpos(self):
+        lineno, column = self.getpos()
+        return (self.filename, lineno, column)
 
     def handle_starttag(self, tag, attrib):
-        pos = self.getpos()
-        self.queue.append((Stream.START, (QName(tag), Attributes(attrib)), pos))
+        pos = self._getpos()
+        self._queue.append((Stream.START, (QName(tag), Attributes(attrib)), pos))
         if tag in self._EMPTY_ELEMS:
-            self.queue.append((Stream.END, QName(tag), pos))
+            self._queue.append((Stream.END, QName(tag), pos))
         else:
             self._open_tags.append(tag)
 
     def handle_endtag(self, tag):
         if tag not in self._EMPTY_ELEMS:
-            pos = self.getpos()
+            pos = self._getpos()
             while self._open_tags:
                 open_tag = self._open_tags.pop()
                 if open_tag.lower() == tag.lower():
                     break
-                self.queue.append((Stream.END, QName(open_tag), pos))
-            self.queue.append((Stream.END, QName(tag), pos))
+                self._queue.append((Stream.END, QName(open_tag), pos))
+            self._queue.append((Stream.END, QName(tag), pos))
 
     def handle_data(self, text):
-        self.queue.append((Stream.TEXT, text, self.getpos()))
+        self._queue.append((Stream.TEXT, text, self._getpos()))
 
     def handle_charref(self, name):
-        self.queue.append((Stream.TEXT, Markup('&#%s;' % name), self.getpos()))
+        self._queue.append((Stream.TEXT, Markup('&#%s;' % name), self._getpos()))
 
     def handle_entityref(self, name):
-        self.queue.append((Stream.TEXT, Markup('&%s;' % name), self.getpos()))
+        self._queue.append((Stream.TEXT, Markup('&%s;' % name), self._getpos()))
 
     def handle_pi(self, data):
         target, data = data.split(maxsplit=1)
         data = data.rstrip('?')
-        self.queue.append((Stream.PI, (target.strip(), data.strip()),
-                           self.getpos()))
+        self._queue.append((Stream.PI, (target.strip(), data.strip()),
+                           self._getpos()))
 
     def handle_comment(self, text):
-        self.queue.append((Stream.COMMENT, text, self.getpos()))
+        self._queue.append((Stream.COMMENT, text, self._getpos()))
 
 
 def HTML(text):