# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1480457598 -3600
# Node ID 639a285a92feb5a62667ca8eeca6010a12cf0164
# Parent  03dad612d9e7c50fde962774f5289cf80fa9f755
Added the index method to sequences. Raise TypeError instances.

diff -r 03dad612d9e7 -r 639a285a92fe lib/__builtins__/sequence.py
--- a/lib/__builtins__/sequence.py	Tue Nov 29 23:12:15 2016 +0100
+++ b/lib/__builtins__/sequence.py	Tue Nov 29 23:13:18 2016 +0100
@@ -62,6 +62,19 @@
 
         return False
 
+    def index(self, value):
+
+        "Return the index of 'value' or raise ValueError."
+
+        i = 0
+        l = len(self)
+        while i < l:
+            if self[i] == value:
+                return i
+            i += 1
+
+        raise ValueError(value)
+
     def __getitem__(self, index):
 
         "Return the item or slice specified by 'index'."
@@ -81,7 +94,7 @@
         # No other kinds of objects are supported as indexes.
 
         else:
-            raise TypeError
+            raise TypeError()
 
     def __setitem__(self, index, value):
 
@@ -102,7 +115,7 @@
         # No other kinds of objects are supported as indexes.
 
         else:
-            raise TypeError
+            raise TypeError()
 
     def __getslice__(self, start, end=None):
 
diff -r 03dad612d9e7 -r 639a285a92fe tests/list.py
--- a/tests/list.py	Tue Nov 29 23:12:15 2016 +0100
+++ b/tests/list.py	Tue Nov 29 23:13:18 2016 +0100
@@ -33,3 +33,11 @@
 print 4 not in l        # True
 print "four" not in l   # False
 print "one" not in l    # True
+
+print l.index(1)        # 0
+print l.index("four")   # 3
+
+try:
+    print l.index(4)    # should raise an exception
+except ValueError, exc:
+    print "l.index(4): failed to find argument", exc.value