1 files changed, 118 insertions, 0 deletions
diff --git a/qpid/python/qpid/lexer.py b/qpid/python/qpid/lexer.py
new file mode 100644
index 0000000000..ec28bbb91a
--- /dev/null
+++ b/qpid/python/qpid/lexer.py
@@ -0,0 +1,118 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+import re
+
+class Type:
+
+  def __init__(self, name, pattern=None):
+    self.name = name
+    self.pattern = pattern
+
+  def __repr__(self):
+    return self.name
+
+class Lexicon:
+
+  def __init__(self):
+    self.types = []
+    self._eof = None
+
+  def define(self, name, pattern):
+    t = Type(name, pattern)
+    self.types.append(t)
+    return t
+
+  def eof(self, name):
+    t = Type(name)
+    self._eof = t
+    return t
+
+  def compile(self):
+    types = self.types[:]
+    joined = "|".join(["(%s)" % t.pattern for t in types])
+    rexp = re.compile(joined)
+    return Lexer(types, self._eof, rexp)
+
+class Token:
+
+  def __init__(self, type, value, input, position):
+    self.type = type
+    self.value = value
+    self.input = input
+    self.position = position
+
+  def line_info(self):
+    return line_info(self.input, self.position)
+
+  def __repr__(self):
+    if self.value is None:
+      return repr(self.type)
+    else:
+      return "%s(%s)" % (self.type, self.value)
+
+
+class LexError(Exception):
+  pass
+
+def line_info(st, pos):
+  idx = 0
+  lineno = 1
+  column = 0
+  line_pos = 0
+  while idx < pos:
+    if st[idx] == "\n":
+      lineno += 1
+      column = 0
+      line_pos = idx
+    column += 1
+    idx += 1
+
+  end = st.find("\n", line_pos)
+  if end < 0:
+    end = len(st)
+  line = st[line_pos:end]
+
+  return line, lineno, column
+
+class Lexer:
+
+  def __init__(self, types, eof, rexp):
+    self.types = types
+    self.eof = eof
+    self.rexp = rexp
+    self.byname = {}
+    for t in self.types + [eof]:
+      self.byname[t.name] = t
+
+  def type(self, name):
+    return self.byname[name]
+
+  def lex(self, st):
+    pos = 0
+    while pos < len(st):
+      m = self.rexp.match(st, pos)
+      if m is None:
+        line, ln, col = line_info(st, pos)
+        raise LexError("unrecognized characters line:%s,%s: %s" % (ln, col, line))
+      else:
+        idx = m.lastindex
+        t = Token(self.types[idx - 1], m.group(idx), st, pos)
+        yield t
+      pos = m.end()
+    yield Token(self.eof, None, st, pos)