# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1481127879 -3600
# Node ID d9053172e0ffd6967bc710f77f052d747e10f9cf
# Parent  120b54816bd4e666036d29d0fc1a82040a9cfed2
Implemented the join method for strings.

diff -r 120b54816bd4 -r d9053172e0ff lib/__builtins__/str.py
--- a/lib/__builtins__/str.py	Wed Dec 07 17:15:12 2016 +0100
+++ b/lib/__builtins__/str.py	Wed Dec 07 17:24:39 2016 +0100
@@ -139,7 +139,30 @@
     def endswith(self, s): pass
     def find(self, sub, start=None, end=None): pass
     def index(self, sub, start=None, end=None): pass
-    def join(self, l): pass
+
+    def join(self, l):
+
+        "Join the elements in 'l' with this string."
+
+        # Empty strings just cause the list elements to be concatenated.
+
+        if not self.__bool__():
+            return str(buffer(l))
+
+        # Non-empty strings join the elements together in a buffer.
+
+        b = buffer()
+        first = True
+
+        for s in l:
+            if first:
+                first = False
+            else:
+                b.append(self)
+            b.append(s)
+
+        return str(b)
+
     def lower(self): pass
     def lstrip(self, chars=None): pass
     def replace(self, old, new, count=None): pass
diff -r 120b54816bd4 -r d9053172e0ff tests/string.py
--- a/tests/string.py	Wed Dec 07 17:15:12 2016 +0100
+++ b/tests/string.py	Wed Dec 07 17:24:39 2016 +0100
@@ -21,4 +21,14 @@
 except ValueError, exc:
     print "ord(s): value is not appropriate", exc.value
 
+l = ["Hello", "world!"]
+s3 = " ".join(l)
+print s3                    # Hello world!
+
+s4 = "".join(l)
+print s4                    # Helloworld!
+
 print hash(s)
+print hash(s2)
+print hash(s3)
+print hash(s4)