# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1317507589 -7200
# Node ID 807beac0d287031baeb7ef93e807a95534ea2d53
# Parent  d254badcda0ab39f390a5c2f8c9daece6254e620
Reintroduced conversion objects, moving state-related classes into a new
converters module, and permitting converters to retain state between operations.

diff -r d254badcda0a -r 807beac0d287 simplex/__init__.py
--- a/simplex/__init__.py	Sat Oct 01 22:06:03 2011 +0200
+++ b/simplex/__init__.py	Sun Oct 02 00:19:49 2011 +0200
@@ -31,7 +31,7 @@
 from simplex.readers import *
 from simplex.iterators import *
 from simplex.accessors import *
-from simplex.state import *
+from simplex.converters import *
 
 import bisect
 
diff -r d254badcda0a -r 807beac0d287 simplex/accessors.py
--- a/simplex/accessors.py	Sat Oct 01 22:06:03 2011 +0200
+++ b/simplex/accessors.py	Sun Oct 02 00:19:49 2011 +0200
@@ -63,11 +63,16 @@
         self.converters = converters
 
     def get_converter(self, converter):
-        return converter or (lambda x: x)
+        return converter and converter.convert or (lambda x: x)
+
+    def reset(self):
+        for converter in self.converters:
+            if converter:
+                converter.reset()
 
     def convert(self, term):
         converters = map(self.get_converter, self.converters)
-        return [converter(value) for converter, value in zip(converters, term)]
+        return [convert(value) for convert, value in zip(converters, term)]
 
     def get_key(self, record):
         key = self.accessor.get_key(record)
diff -r d254badcda0a -r 807beac0d287 simplex/converters.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/simplex/converters.py	Sun Oct 02 00:19:49 2011 +0200
@@ -0,0 +1,70 @@
+#!/usr/bin/env python
+
+"""
+Converters for use with accessors.
+
+Copyright (C) 2011 Paul Boddie <paul@boddie.org.uk>
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; either version 3 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along
+with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+
+from os.path import commonprefix
+
+class Converter:
+
+    "A generic converter."
+
+    def reset(self):
+        pass
+
+    def convert(self, value):
+        return value
+
+class CommonPrefixState(Converter):
+
+    "A class whose instances maintain common prefix state."
+
+    def __init__(self, initial=""):
+        self.initial = initial
+        self.reset()
+
+    def reset(self):
+        self.value = self.initial
+
+class CommonPrefixDecoder(CommonPrefixState):
+
+    "A class whose instances decode common prefix information."
+
+    def convert(self, common_plus_suffix):
+        common, suffix = common_plus_suffix
+        self.value = self.value[:common] + suffix
+        return self.value
+
+class CommonPrefixEncoder(CommonPrefixState):
+
+    "A class whose instances encode common prefix information."
+
+    def convert(self, value):
+        common = len(commonprefix((self.value, value)))
+        suffix = value[common:]
+        self.value = value
+        return common, suffix
+
+class NumericDecoder(Converter):
+
+    "A class which decodes numbers."
+
+    def convert(self, value):
+        return int(value)
+
+# vim: tabstop=4 expandtab shiftwidth=4
diff -r d254badcda0a -r 807beac0d287 simplex/state.py
--- a/simplex/state.py	Sat Oct 01 22:06:03 2011 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,53 +0,0 @@
-#!/usr/bin/env python
-
-"""
-State management classes for iterators.
-
-Copyright (C) 2011 Paul Boddie <paul@boddie.org.uk>
-
-This program is free software; you can redistribute it and/or modify it under
-the terms of the GNU General Public License as published by the Free Software
-Foundation; either version 3 of the License, or (at your option) any later
-version.
-
-This program is distributed in the hope that it will be useful, but WITHOUT ANY
-WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
-PARTICULAR PURPOSE.  See the GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License along
-with this program.  If not, see <http://www.gnu.org/licenses/>.
-"""
-
-from os.path import commonprefix
-
-class CommonPrefixState:
-
-    "A class whose instances maintain common prefix state."
-
-    def __init__(self, initial=""):
-        self.initial = initial
-        self.reset()
-
-    def reset(self):
-        self.value = self.initial
-
-class CommonPrefixDecoder(CommonPrefixState):
-
-    "A class whose instances decode common prefix information."
-
-    def update(self, common_plus_suffix):
-        common, suffix = common_plus_suffix
-        self.value = self.value[:common] + suffix
-        return self.value
-
-class CommonPrefixEncoder(CommonPrefixState):
-
-    "A class whose instances encode common prefix information."
-
-    def update(self, value):
-        common = len(commonprefix((self.value, value)))
-        suffix = value[common:]
-        self.value = value
-        return common, suffix
-
-# vim: tabstop=4 expandtab shiftwidth=4