Add RbDefineVariable

_tools/ruby_h_to_go/ruby_h_to_go.rb

@@ -128,6 +128,14 @@ def generate_go_file(definition:, header_dir:)
     end
   end
 
+  definition[:args].each do |c_arg|
+    case c_arg[:name]
+    when "var"
+      # `var` is reserved in Go
+      c_arg[:name] = "v"
+    end
+  end
+
   go_function_name = snake_to_camel(definition[:function_name])
   go_function_args = definition[:args].map do |c_arg|
     "#{c_arg[:name]} #{ruby_c_type_to_go_type(c_arg[:type], type: :arg)}"

ruby-internal-variable.go

@@ -0,0 +1,20 @@
+package ruby
+
+/*
+#include "ruby.h"
+*/
+import "C"
+
+// c.f. https://github.com/ruby/ruby/blob/master/include/ruby/internal/variable.h
+
+// RbDefineVariable calls `rb_define_variable` in C
+//
+// Original definition is following
+//
+//	void rb_define_variable(const char *name, VALUE *var)
+func RbDefineVariable(name string, v *VALUE) {
+	char, clean := string2Char(name)
+	defer clean()
+
+	C.rb_define_variable(char, (*C.VALUE)(v))
+}

testdata/dummy/ext/dummy/tests.go

@@ -29,6 +29,7 @@ VALUE rb_dummy_tests_rb_ary_push(VALUE self, VALUE ary, VALUE elem);
 VALUE rb_dummy_tests_rb_ary_pop(VALUE self, VALUE ary);
 VALUE rb_dummy_tests_rb_ary_shift(VALUE self, VALUE ary);
 VALUE rb_dummy_tests_rb_ary_unshift(VALUE self, VALUE ary, VALUE elem);
+void  rb_dummy_tests_rb_define_variable(VALUE self, VALUE name, VALUE v);
 */
 import "C"
 
@@ -255,6 +256,12 @@ func rb_dummy_tests_rb_ary_unshift(_ C.VALUE, ary C.VALUE, elem C.VALUE) C.VALUE
 	return C.VALUE(ret)
 }
 
+//export rb_dummy_tests_rb_define_variable
+func rb_dummy_tests_rb_define_variable(_ C.VALUE, name C.VALUE, v C.VALUE) {
+	strName := ruby.Value2String(ruby.VALUE(name))
+	ruby.RbDefineVariable(strName, (*ruby.VALUE)(&v))
+}
+
 // defineMethodsToDummyTests define methods in Dummy::Tests
 func defineMethodsToDummyTests(rb_mDummy ruby.VALUE) {
 	rb_cTests := ruby.RbDefineClassUnder(rb_mDummy, "Tests", ruby.VALUE(C.rb_cObject))
@@ -287,4 +294,5 @@ func defineMethodsToDummyTests(rb_mDummy ruby.VALUE) {
 	ruby.RbDefineSingletonMethod(rb_cTests, "rb_ary_pop", C.rb_dummy_tests_rb_ary_pop, 1)
 	ruby.RbDefineSingletonMethod(rb_cTests, "rb_ary_shift", C.rb_dummy_tests_rb_ary_shift, 1)
 	ruby.RbDefineSingletonMethod(rb_cTests, "rb_ary_unshift", C.rb_dummy_tests_rb_ary_unshift, 2)
+	ruby.RbDefineSingletonMethod(rb_cTests, "rb_define_variable", C.rb_dummy_tests_rb_define_variable, 2)
 }

testdata/dummy/sig/dummy/tests.rbs

@@ -36,6 +36,7 @@ module Dummy
     def self.rb_ary_pop: ([] ary) -> untyped
     def self.rb_ary_shift: ([] ary) -> untyped
     def self.rb_ary_unshift: ([] ary, untyped elem) -> []
+    def self.rb_define_variable: (string name, untyped var) -> void
 
     private
     def nop_rb_define_private_method: () -> void

testdata/dummy/test/dummy/tests_test.rb

@@ -170,5 +170,14 @@ class RbAttrTest < Test::Unit::TestCase
     test "#nop_rb_define_protected_method" do
       assert { Dummy::Tests.protected_instance_methods(false).include?(:nop_rb_define_protected_method) }
     end
+
+    # rubocop:disable Style/GlobalVars this is test for global variable
+    test ".rb_define_variable" do
+      Dummy::Tests.rb_define_variable("$global_var", 1)
+      assert { $global_var == 1 }
+    ensure
+      $global_var = nil
+    end
+    # rubocop:enable Style/GlobalVars
   end
 end