Added *MrbValue.GetInstanceVariable, *MrbValue.SetInstanceVariable, *…

…Mrb.GetGlobalVariable, *Mrb.SetGlobalVariable and their underlying C methods to allow Go to pass variables to/from Ruby.

gomruby.h

@@ -252,4 +252,20 @@ static inline struct RObject* _go_mrb_getobj(mrb_value v) {
   return mrb_obj_ptr(v);
 }
 
+static inline void _go_mrb_iv_set(mrb_state *m, mrb_value self, mrb_sym sym, mrb_value v) {
+  mrb_iv_set(m, self, sym, v);
+}
+
+static inline mrb_value _go_mrb_iv_get(mrb_state *m, mrb_value self, mrb_sym sym) {
+  return mrb_iv_get(m, self, sym);
+}
+
+static inline void _go_mrb_gv_set(mrb_state *m, mrb_sym sym, mrb_value v) {
+  mrb_gv_set(m, sym, v);
+}
+
+static inline mrb_value _go_mrb_gv_get(mrb_state *m, mrb_sym sym) {
+  return mrb_gv_get(m, sym);
+}
+
 #endif

mruby.go

@@ -13,6 +13,22 @@ type Mrb struct {
 	state *C.mrb_state
 }
 
+// GetGlobalVariable returns the value of the global variable by the given name.
+func (m *Mrb) GetGlobalVariable(name string) *MrbValue {
+	cs := C.CString(name)
+	defer C.free(unsafe.Pointer(cs))
+	return newValue(m.state, C._go_mrb_gv_get(m.state, C.mrb_intern_cstr(m.state, cs)))
+}
+
+// SetGlobalVariable sets the value of the global variable by the given name.
+func (m *Mrb) SetGlobalVariable(name string, value Value) {
+	cs := C.CString(name)
+	defer C.free(unsafe.Pointer(cs))
+
+	v := value.MrbValue(m)
+	C._go_mrb_gv_set(m.state, C.mrb_intern_cstr(m.state, cs), v.value)
+}
+
 // ArenaIndex represents the index into the arena portion of the GC.
 //
 // See ArenaSave for more information.

value.go

@@ -41,6 +41,20 @@ func init() {
 	Nil = [0]byte{}
 }
 
+// SetInstanceVariable sets an instance variable on this value.
+func (v *MrbValue) SetInstanceVariable(variable string, value *MrbValue) {
+	cs := C.CString(variable)
+	defer C.free(unsafe.Pointer(cs))
+	C._go_mrb_iv_set(v.state, v.value, C.mrb_intern_cstr(v.state, cs), value.value)
+}
+
+// GetInstanceVariable gets an instance variable on this value.
+func (v *MrbValue) GetInstanceVariable(variable string) *MrbValue {
+	cs := C.CString(variable)
+	defer C.free(unsafe.Pointer(cs))
+	return newValue(v.state, C._go_mrb_iv_get(v.state, v.value, C.mrb_intern_cstr(v.state, cs)))
+}
+
 // Call calls a method with the given name and arguments on this
 // value.
 func (v *MrbValue) Call(method string, args ...Value) (*MrbValue, error) {