Merge pull request #597 from kachick/implement-string-concat

Implement String#concat

spec/tags/core/string/concat_tags.txt

@@ -1,15 +1,12 @@
-fails:String#concat concatenates the given argument to self and returns self
 fails:String#concat converts the given argument to a String using to_str
 fails:String#concat raises a TypeError if the given argument can't be converted to a String
-fails:String#concat raises a RuntimeError when self is frozen
 fails:String#concat taints self if other is tainted
 fails:String#concat untrusts self if other is untrusted
 fails:String#concat with Integer concatencates the argument interpreted as a codepoint
 fails:String#concat with Integer returns a ASCII-8BIT string if self is US-ASCII and the argument is between 128-255 (inclusive)
 fails:String#concat with Integer raises RangeError if the argument is an invalid codepoint for self's encoding
 fails:String#concat with Integer raises RangeError if the argument is negative
 fails:String#concat with Integer doesn't call to_int on its argument
-fails:String#concat with Integer raises a RuntimeError when self is frozen
 fails:String#concat when self is in an ASCII-incompatible encoding incompatible with the argument's encoding uses self's encoding if both are empty
 fails:String#concat when self is in an ASCII-incompatible encoding incompatible with the argument's encoding uses self's encoding if the argument is empty
 fails:String#concat when self is in an ASCII-incompatible encoding incompatible with the argument's encoding uses the argument's encoding if self is empty

tests/objects/test_stringobject.py

@@ -13,6 +13,8 @@ def test_new(self, space):
     def test_lshift(self, space):
         w_res = space.execute('return "abc" << "def" << "ghi"')
         assert space.str_w(w_res) == "abcdefghi"
+        w_res = space.execute('return "abc".concat("def").concat("ghi")')
+        assert space.str_w(w_res) == "abcdefghi"
 
     def test_plus(self, space):
         w_res = space.execute('return "abc" + "def" + "ghi"')

topaz/objects/stringobject.py

@@ -446,6 +446,7 @@ def method_times(self, space, times):
         return self.strategy.mul(space, self.str_storage, times)
 
     @classdef.method("<<")
+    @classdef.method("concat")
     @check_frozen()
     def method_lshift(self, space, w_other):
         assert isinstance(w_other, W_StringObject)