Merge pull request #758 from kachick/implement-string-prepend

Implement String#prepend

spec/tags/core/string/prepend_tags.txt

@@ -1,6 +1 @@
-fails:String#prepend prepends the given argument to self and returns self
-fails:String#prepend converts the given argument to a String using to_str
-fails:String#prepend raises a TypeError if the given argument can't be converted to a String
-fails:String#prepend raises a RuntimeError when self if frozen
-fails:String#prepend works when given a subclass instance
 fails:String#prepend taints self if other is tainted

topaz/objects/stringobject.py

@@ -1125,6 +1125,13 @@ def method_insert(self, space, index, other):
         self.strategy.insert(self.str_storage, index, other)
         return self
 
+    @classdef.method("prepend", other="str")
+    @check_frozen()
+    def method_prepend(self, space, other):
+        self.strategy.to_mutable(space, self)
+        self.strategy.insert(self.str_storage, 0, other)
+        return self
+
     @classdef.method("strip!")
     @check_frozen()
     def method_strip_i(self, space):