diff options
| -rw-r--r-- | proc.c | 25 | ||||
| -rw-r--r-- | test/ruby/test_method.rb | 34 |
2 files changed, 59 insertions, 0 deletions
@@ -3100,6 +3100,30 @@ proc_compose(VALUE self, VALUE g) } /* + * call-seq: + * meth * g -> a_proc + * + * Returns a proc that is the composition of this method and the given proc <i>g</i>. + * The returned proc takes a variable number of arguments, calls <i>g</i> with them + * then calls this method with the result. + * + * def f(x) + * x * 2 + * end + * + * f = self.method(:f) + * g = proc {|x, y| x + y } + * h = f * g + * p h.call(1, 2) #=> 6 + */ +static VALUE +rb_method_compose(VALUE self, VALUE g) +{ + VALUE proc = method_to_proc(self); + return proc_compose(proc, g); +} + +/* * Document-class: LocalJumpError * * Raised when Ruby can't yield as requested. @@ -3222,6 +3246,7 @@ Init_Proc(void) rb_define_method(rb_cMethod, "call", rb_method_call, -1); rb_define_method(rb_cMethod, "===", rb_method_call, -1); rb_define_method(rb_cMethod, "curry", rb_method_curry, -1); + rb_define_method(rb_cMethod, "*", rb_method_compose, 1); rb_define_method(rb_cMethod, "[]", rb_method_call, -1); rb_define_method(rb_cMethod, "arity", method_arity_m, 0); rb_define_method(rb_cMethod, "inspect", method_inspect, 0); diff --git a/test/ruby/test_method.rb b/test/ruby/test_method.rb index fe0171dd57..80a2669633 100644 --- a/test/ruby/test_method.rb +++ b/test/ruby/test_method.rb @@ -1040,4 +1040,38 @@ class TestMethod < Test::Unit::TestCase assert_operator(0.method(:<), :===, 5) assert_not_operator(0.method(:<), :===, -5) end + + def test_compose_with_method + c = Class.new { + def f(x) x * 2 end + def g(x) x + 1 end + } + f = c.new.method(:f) + g = c.new.method(:g) + h = f * g + + assert_equal(6, h.call(2)) + end + + def test_compose_with_proc + c = Class.new { + def f(x) x * 2 end + } + f = c.new.method(:f) + g = proc {|x| x + 1} + h = f * g + + assert_equal(6, h.call(2)) + end + + def test_compose_with_nonproc_or_method + c = Class.new { + def f(x) x * 2 end + } + f = c.new.method(:f) + + assert_raise(TypeError) { + f * 5 + } + end end |