Implement Object#tap

1 files changed, 19 insertions, 0 deletions

diff --git a/mrbgems/mruby-object-ext/mrblib/object.rb b/mrbgems/mruby-object-ext/mrblib/object.rb
new file mode 100644
index 000000000..581156cb0
--- /dev/null
+++ b/mrbgems/mruby-object-ext/mrblib/object.rb
@@ -0,0 +1,19 @@
+class Object
+  ##
+  #  call-seq:
+  #     obj.tap{|x|...}    -> obj
+  #
+  #  Yields <code>x</code> to the block, and then returns <code>x</code>.
+  #  The primary purpose of this method is to "tap into" a method chain,
+  #  in order to perform operations on intermediate results within the chain.
+  #
+  #  (1..10)                .tap {|x| puts "original: #{x.inspect}"}
+  #    .to_a                .tap {|x| puts "array: #{x.inspect}"}
+  #    .select {|x| x%2==0} .tap {|x| puts "evens: #{x.inspect}"}
+  #    .map { |x| x*x }     .tap {|x| puts "squares: #{x.inspect}"}
+  #
+  def tap
+    yield self
+    self
+  end
+end