Made Result type to access status/value easier

pyresult/operators.py

@@ -4,7 +4,6 @@
 from toolz import curry
 
 from pyresult.result import (
-    VALUE_IDX,
     ok,
     error,
     result,
@@ -19,7 +18,8 @@ def errmap(func, res):
 
     errmap: (x -> y) -> Result a x -> Result a y
     '''
-    return error(func(res[VALUE_IDX])) if is_error(res) else res
+    res = result(res)
+    return error(func(res.value)) if is_error(res) else res
 
 
 @curry
@@ -28,7 +28,8 @@ def rmap(func, res):
 
     rmap: (a -> value) -> Result a -> Result value
     '''
-    return ok(func(res[VALUE_IDX])) if is_ok(res) else res
+    res = result(res)
+    return ok(func(res.value)) if is_ok(res) else res
 
 
 @curry
@@ -37,7 +38,8 @@ def and_then(func, res):
 
     and_then: (a -> Result b x) -> Result a x -> Result b x
     '''
-    return result(func(res[VALUE_IDX])) if is_ok(res) else res
+    res = result(res)
+    return result(func(res.value)) if is_ok(res) else res
 
 
 @curry
@@ -46,7 +48,8 @@ def and_else(func, res):
 
     and_else: (x -> Result b x) -> Result a x -> Result a x
     '''
-    return result(func(res[VALUE_IDX])) if is_error(res) else res
+    res = result(res)
+    return result(func(res.value)) if is_error(res) else res
 
 
 @curry
@@ -61,10 +64,11 @@ def fold(res):
     err = [None]*len_res
 
     for i, e in enumerate(res):
+        e = result(e)
         if is_ok(e):
-            val[i] = e[VALUE_IDX]
+            val[i] = e.value
         else:
-            err[i] = e[VALUE_IDX]
+            err[i] = e.value
 
     if None in val:
         return error(err)
@@ -77,4 +81,5 @@ def resolve(res):
 
     resolve: Result (Result a x) x -> Result a x
     '''
-    return res if is_error(res) else result(res[VALUE_IDX])
+    res = result(res)
+    return res if is_error(res) else result(res.value)

pyresult/result.py

@@ -1,12 +1,12 @@
 # -*- coding: utf-8 -*-
 '''Result pattern implementation'''
 
+import collections
 
 OK = 'Ok'
 ERROR = 'Error'
 
-STATUS_IDX = 0
-VALUE_IDX = 1
+Result = collections.namedtuple('Result', ('status', 'value'))
 
 
 class ResultError(Exception):
@@ -16,37 +16,39 @@ class ResultError(Exception):
 
 def ok(val):  # pylint: disable=invalid-name
     '''Create Ok result'''
-    return (OK, val)
+    return Result(OK, val)
 
 
 def error(msg):
     '''Create error result'''
-    return (ERROR, msg)
+    return Result(ERROR, msg)
 
 
 def result(res):
     '''Check value is result'''
     if not isinstance(res, tuple) or len(res) != 2:
-        raise ResultError(u'Error: Value \'{0}\' isn\'t 2-tuple.'.format(res))
-    if res[STATUS_IDX] != OK and res[STATUS_IDX] != ERROR:
+        raise ResultError(u'Error: Value \'{0!r}\' isn\'t 2-tuple.'.format(res))
+    res = Result(*res)
+    if res.status != OK and res.status != ERROR:
         raise ResultError(
-            u'Error: Value \'{0}\' isn\'t \'Ok\' or \'Error\'.'.format(res)
+            u'Error: Value \'{0!r}\' isn\'t \'Ok\' or \'Error\'.'.format(res)
         )
     return res
 
 
 def is_ok(res):
     '''Check result is Ok'''
-    return result(res)[STATUS_IDX] == OK
+    return result(res).status == OK
 
 
 def is_error(res):
     '''Check result is Error'''
-    return result(res)[STATUS_IDX] == ERROR
+    return result(res).status == ERROR
 
 
 def value(res):
     '''Return stored value in Result'''
+    res = result(res)
     if is_error(res):
-        raise ResultError(res[VALUE_IDX])
-    return res[VALUE_IDX]
+        raise ResultError(res.value)
+    return res.value

tests/test_result.py

@@ -45,7 +45,7 @@ def test_result_ok_tuple():
 
 def test_result_ok_2tuple():
     with pytest.raises(ResultError):
-        result((OK))
+        result((OK,))
 
 
 def test_result_error_tuple():
@@ -55,7 +55,7 @@ def test_result_error_tuple():
 
 def test_result_error_2tuple():
     with pytest.raises(ResultError):
-        result((ERROR))
+        result((ERROR,))
 
 
 def test_result_isnt_ok_either_error():