kernel.c: add `__method__`; ref #4468

mrbgems/mruby-kernel-ext/src/kernel.c

@@ -5,6 +5,7 @@
 #include <mruby/range.h>
 #include <mruby/string.h>
 #include <mruby/numeric.h>
+#include <mruby/proc.h>
 #include <mruby/presym.h>
 
 static mrb_value
@@ -64,6 +65,27 @@ mrb_f_caller(mrb_state *mrb, mrb_value self)
   return mrb_ary_new_from_values(mrb, n, RARRAY_PTR(bt)+lev+1);
 }
 
+/*
+ *  call-seq:
+ *     __method__         -> symbol
+ *
+ *  Returns the called name of the current method as a Symbol.
+ *  If called outside of a method, it returns <code>nil</code>.
+ *
+ */
+static mrb_value
+mrb_f_method(mrb_state *mrb, mrb_value self)
+{
+  mrb_callinfo *ci = mrb->c->ci;
+  ci--;
+  if (ci->proc->e.env->tt == MRB_TT_ENV && ci->proc->e.env->mid)
+    return mrb_symbol_value(ci->proc->e.env->mid);
+  else if (ci->mid)
+    return mrb_symbol_value(ci->mid);
+  else
+    return mrb_nil_value();
+}
+
 /*
  *  call-seq:
  *     __callee__         -> symbol
@@ -246,6 +268,7 @@ mrb_mruby_kernel_ext_gem_init(mrb_state *mrb)
 
   mrb_define_module_function(mrb, krn, "fail", mrb_f_raise, MRB_ARGS_OPT(2));
   mrb_define_module_function(mrb, krn, "caller", mrb_f_caller, MRB_ARGS_OPT(2));
+  mrb_define_method(mrb, krn, "__method__", mrb_f_method, MRB_ARGS_NONE());
   mrb_define_method(mrb, krn, "__callee__", mrb_f_callee, MRB_ARGS_NONE());
   mrb_define_module_function(mrb, krn, "Integer", mrb_f_integer, MRB_ARGS_ARG(1,1));
 #ifndef MRB_NO_FLOAT

mrbgems/mruby-kernel-ext/test/kernel.rb

@@ -37,27 +37,30 @@ assert('Kernel.caller, Kernel#caller') do
   assert_raise(TypeError) { c.new.baz(nil) }
 end
 
-assert('Kernel#__callee__') do
+assert('Kernel#__method__') do
   c = Class.new do
-    def m1; __callee__ end
-    define_method(:m2) {__callee__}
+    def m1; __method__ end
+    define_method(:m2) {__method__}
     alias m3 m1
     alias_method :m4, :m2
   end
   assert_equal(:m1, c.new.m1)
   assert_equal(:m2, c.new.m2)
-  assert_equal(:m3, c.new.m3)
-  assert_equal(:m4, c.new.m4)
+  assert_equal(:m1, c.new.m3)
+  assert_equal(:m2, c.new.m4)
+end
 
+assert('Kernel#__callee__') do
   c = Class.new do
-    [:m1, :m2].each do |m|
-      define_method(m) do
-        __callee__
-      end
-    end
+    def m1; __callee__ end
+    define_method(:m2) {__callee__}
+    alias m3 m1
+    alias_method :m4, :m2
   end
   assert_equal(:m1, c.new.m1)
   assert_equal(:m2, c.new.m2)
+  assert_equal(:m3, c.new.m3)
+  assert_equal(:m4, c.new.m4)
 end
 
 assert('Kernel#Integer') do