Added Symbol#start_with? and Symbol#end_with? method. [Feature #16348]

NEWS

@@ -397,6 +397,10 @@ RubyVM::
 
 String::
 
+  New methods::
+
+    * Added Symbol#start_with? and Symbol#end_with? method.  [Feature #16348]
+
   Unicode::
 
     * Update Unicode version and Emoji version from 11.0.0 to

string.c

@@ -11075,6 +11075,46 @@ sym_swapcase(int argc, VALUE *argv, VALUE sym)
     return rb_str_intern(rb_str_swapcase(argc, argv, rb_sym2str(sym)));
 }
 
+/*
+ *  call-seq:
+ *     sym.start_with?([prefixes]+)   -> true or false
+ *
+ *  Returns true if +sym+ starts with one of the +prefixes+ given.
+ *  Each of the +prefixes+ should be a String or a Regexp.
+ *
+ *    :hello.start_with?("hell")               #=> true
+ *    :hello.start_with?(/H/i)                 #=> true
+ *
+ *    # returns true if one of the prefixes matches.
+ *    :hello.start_with?("heaven", "hell")     #=> true
+ *    :hello.start_with?("heaven", "paradise") #=> false
+ */
+
+static VALUE
+sym_start_with(int argc, VALUE *argv, VALUE sym)
+{
+    return rb_str_start_with(argc, argv, rb_sym2str(sym));
+}
+
+/*
+ *  call-seq:
+ *     sym.end_with?([suffixes]+)   -> true or false
+ *
+ *  Returns true if +sym+ ends with one of the +suffixes+ given.
+ *
+ *    :hello.end_with?("ello")               #=> true
+ *
+ *    # returns true if one of the +suffixes+ matches.
+ *    :hello.end_with?("heaven", "ello")     #=> true
+ *    :hello.end_with?("heaven", "paradise") #=> false
+ */
+
+static VALUE
+sym_end_with(int argc, VALUE *argv, VALUE sym)
+{
+    return rb_str_end_with(argc, argv, rb_sym2str(sym));
+}
+
 /*
  * call-seq:
  *   sym.encoding   -> encoding
@@ -11361,5 +11401,8 @@ Init_String(void)
     rb_define_method(rb_cSymbol, "capitalize", sym_capitalize, -1);
     rb_define_method(rb_cSymbol, "swapcase", sym_swapcase, -1);
 
+    rb_define_method(rb_cSymbol, "start_with?", sym_start_with, -1);
+    rb_define_method(rb_cSymbol, "end_with?", sym_end_with, -1);
+
     rb_define_method(rb_cSymbol, "encoding", sym_encoding, 0);
 }

test/ruby/test_symbol.rb

@@ -560,4 +560,27 @@ class TestSymbol < Test::Unit::TestCase
       puts :a == :a
     RUBY
   end
+
+  def test_start_with?
+    assert_equal(true, :hello.start_with?("hel"))
+    assert_equal(false, :hello.start_with?("el"))
+    assert_equal(true, :hello.start_with?("el", "he"))
+
+    bug5536 = '[ruby-core:40623]'
+    assert_raise(TypeError, bug5536) {:str.start_with? :not_convertible_to_string}
+
+    assert_equal(true, :hello.start_with?(/hel/))
+    assert_equal("hel", $&)
+    assert_equal(false, :hello.start_with?(/el/))
+    assert_nil($&)
+  end
+
+  def test_end_with?
+    assert_equal(true, :hello.end_with?("llo"))
+    assert_equal(false, :hello.end_with?("ll"))
+    assert_equal(true, :hello.end_with?("el", "lo"))
+
+    bug5536 = '[ruby-core:40623]'
+    assert_raise(TypeError, bug5536) {:str.end_with? :not_convertible_to_string}
+  end
 end