From 66fb4c28224ba84e8682c85cf363c7e4193dcca8 Mon Sep 17 00:00:00 2001
From: "W. Trevor King" <wking@drexel.edu>
Date: Mon, 19 Mar 2012 09:31:28 -0400
Subject: [PATCH] Add attributes to PyComediError to make intelligent error
 handling easier.

---
 pycomedi/__init__.py | 13 ++++++++++++-
 pycomedi/_error.pyx  | 19 ++++++++++++-------
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/pycomedi/__init__.py b/pycomedi/__init__.py
index bec6914..673ef88 100644
--- a/pycomedi/__init__.py
+++ b/pycomedi/__init__.py
@@ -36,4 +36,15 @@ del h, f
 
 class PyComediError (Exception):
     "Error in pycomedi"
-    pass
+    def __init__(self, function_name=None, ret=None, comedi_msg=None,
+                 error_msg=None):
+        self.function_name = function_name
+        self.ret = ret
+        self.comedi_msg = comedi_msg
+        self.error_msg = error_msg
+        if error_msg:
+            msg = '{} ({}): {} ({})'.format(
+                function_name, error_msg, comedi_msg, ret)
+        else:
+            msg = '{}: {} ({})'.format(function_name, comedi_msg, ret)
+        super(PyComediError, self).__init__(msg)
diff --git a/pycomedi/_error.pyx b/pycomedi/_error.pyx
index 6a2245c..4cd4cea 100644
--- a/pycomedi/_error.pyx
+++ b/pycomedi/_error.pyx
@@ -24,9 +24,10 @@ from pycomedi import PyComediError as _PyComediError
 cimport _comedilib_h
 
 
-def raise_error(function_name='', ret=None, error_msg=None):
+def raise_error(function_name=None, ret=None, error_msg=None):
     """Report an error while executing a comedilib function
 
+    >>> from pycomedi import PyComediError
     >>> raise_error(function_name='myfn', ret=-1)
     Traceback (most recent call last):
       ...
@@ -35,15 +36,19 @@ def raise_error(function_name='', ret=None, error_msg=None):
     Traceback (most recent call last):
       ...
     PyComediError: myfn (some error): Success (-1)
+    >>> try:
+    ...     raise_error(function_name='myfn', ret=-1)
+    ... except PyComediError, e:
+    ...     print(e.function_name)
+    ...     print(e.ret)
+    myfn
+    -1
     """
     errno = _comedilib_h.comedi_errno()
     comedi_msg = _comedilib_h.comedi_strerror(errno)
-    #_comedilib_h.comedi_perror(function_name)
-    if error_msg:
-        msg = '%s (%s): %s (%s)' % (function_name, error_msg, comedi_msg, ret)
-    else:
-        msg = '%s: %s (%s)' % (function_name, comedi_msg, ret)
-    raise _PyComediError(msg)
+    raise _PyComediError(
+        function_name=function_name, ret=ret, comedi_msg=comedi_msg,
+        error_msg=error_msg)
 
 
 def _comedi_getter(name, is_invalid):
-- 
2.26.2