Merge branch 'pr-add-new-api-mrb_true_or_false_value' of https://github.com/monaka/mruby into monaka-pr-add-new-api-mrb_true_or_false_value

11 files changed, 232 insertions, 199 deletions

diff --git a/src/array.c b/src/array.c
index e704aa2c4..82c4625bd 100644
--- a/src/array.c
+++ b/src/array.c
@@ -878,7 +878,7 @@ mrb_ary_empty_p(mrb_state *mrb, mrb_value self)
 {
   struct RArray *a = mrb_ary_ptr(self);
 
-  return ((a->len == 0)? mrb_true_value(): mrb_false_value());
+  return mrb_true_or_false_value(a->len == 0);
 }
 
 mrb_value
@@ -1059,31 +1059,39 @@ static mrb_value
 mrb_ary_equal(mrb_state *mrb, mrb_value ary1)
 {
   mrb_value ary2;
+  mrb_bool equal_p;
 
   mrb_get_args(mrb, "o", &ary2);
-  if (mrb_obj_equal(mrb, ary1, ary2)) return mrb_true_value();
-  if (mrb_special_const_p(ary2)) return mrb_false_value();
-  if (!mrb_array_p(ary2)) {
+  if (mrb_obj_equal(mrb, ary1, ary2)) {
+    equal_p = 1;
+  }
+  else if (mrb_special_const_p(ary2)) {
+    equal_p = 0;
+  }
+  else if (!mrb_array_p(ary2)) {
     if (!mrb_respond_to(mrb, ary2, mrb_intern(mrb, "to_ary"))) {
-        return mrb_false_value();
-    }
-    if (mrb_equal(mrb, ary2, ary1)){
-      return mrb_true_value();
+        equal_p = 0;
     }
     else {
-      return mrb_false_value();
+      equal_p = mrb_equal(mrb, ary2, ary1);
     }
   }
-  if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return mrb_false_value();
+  else if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) {
+    equal_p = 0;
+  }
   else {
     mrb_int i;
 
+    equal_p = 1;
     for (i=0; i<RARRAY_LEN(ary1); i++) {
-      if (!mrb_equal(mrb, ary_elt(ary1, i), ary_elt(ary2, i)))
-        return mrb_false_value();
+      if (!mrb_equal(mrb, ary_elt(ary1, i), ary_elt(ary2, i))) {
+        equal_p = 0;
+        break;
+      }
     }
-    return mrb_true_value();
   }
+
+  return mrb_true_or_false_value(equal_p);
 }
 
 /* 15.2.12.5.34 (x) */
@@ -1099,20 +1107,30 @@ static mrb_value
 mrb_ary_eql(mrb_state *mrb, mrb_value ary1)
 {
   mrb_value ary2;
+  mrb_bool eql_p;
 
   mrb_get_args(mrb, "o", &ary2);
-  if (mrb_obj_equal(mrb, ary1, ary2)) return mrb_true_value();
-  if (!mrb_array_p(ary2)) return mrb_false_value();
-  if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return mrb_false_value();
+  if (mrb_obj_equal(mrb, ary1, ary2)) {
+    eql_p = 1;
+  }
+  else if (!mrb_array_p(ary2)) {
+    eql_p = 0;
+  }
+  else if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) {
+    eql_p = 0;
+  }
   else {
     mrb_int i;
-
+    eql_p = 1;
     for (i=0; i<RARRAY_LEN(ary1); i++) {
-      if (!mrb_eql(mrb, ary_elt(ary1, i), ary_elt(ary2, i)))
-        return mrb_false_value();
+      if (!mrb_eql(mrb, ary_elt(ary1, i), ary_elt(ary2, i))) {
+	eql_p = 0;
+	break;
+      }
     }
-    return mrb_true_value();
   }
+
+  return mrb_true_or_false_value(eql_p);
 }
 
 void
diff --git a/src/class.c b/src/class.c
index 01b383fa0..9f86a7c02 100644
--- a/src/class.c
+++ b/src/class.c
@@ -1090,9 +1090,7 @@ mrb_bob_init(mrb_state *mrb, mrb_value cv)
 static mrb_value
 mrb_bob_not(mrb_state *mrb, mrb_value cv)
 {
-  if (mrb_test(cv))
-    return mrb_false_value();
-  return mrb_true_value();
+  return mrb_true_or_false_value(!mrb_test(cv));
 }
 
 /* 15.3.1.3.30 */
@@ -1495,12 +1493,12 @@ static mrb_value
 mrb_mod_cvar_defined(mrb_state *mrb, mrb_value mod)
 {
   mrb_sym id;
+  mrb_bool defined_p;
   mrb_get_args(mrb, "n", &id);
 
   check_cv_name(mrb, id);
-  if(mrb_cv_defined(mrb, mod, id))
-    return mrb_true_value();
-  return mrb_false_value();
+  defined_p = mrb_cv_defined(mrb, mod, id);
+  return mrb_true_or_false_value(defined_p);
 }
 
 /* 15.2.2.4.17 */
@@ -1636,12 +1634,11 @@ static mrb_value
 mrb_mod_method_defined(mrb_state *mrb, mrb_value mod)
 {
   mrb_sym id;
+  mrb_bool method_defined_p;
 
   mrb_get_args(mrb, "n", &id);
-  if (mrb_obj_respond_to(mrb_class_ptr(mod), id)) {
-    return mrb_true_value();
-  }
-  return mrb_false_value();
+  method_defined_p = mrb_obj_respond_to(mrb_class_ptr(mod), id);
+  return mrb_true_or_false_value(method_defined_p);
 }
 
 static void
@@ -1702,13 +1699,13 @@ mrb_value
 mrb_mod_const_defined(mrb_state *mrb, mrb_value mod)
 {
   mrb_sym id;
+  mrb_bool const_defined_p;
 
   mrb_get_args(mrb, "n", &id);
   check_const_name(mrb, id);
-  if(mrb_const_defined(mrb, mod, id)) {
-    return mrb_true_value();
-  }
-  return mrb_false_value();
+  const_defined_p = mrb_const_defined(mrb, mod, id);
+
+  return mrb_true_or_false_value(const_defined_p);
 }
 
 mrb_value
@@ -1752,11 +1749,12 @@ static mrb_value
 mrb_mod_eqq(mrb_state *mrb, mrb_value mod)
 {
   mrb_value obj;
+  mrb_bool eqq;
 
   mrb_get_args(mrb, "o", &obj);
-  if (!mrb_obj_is_kind_of(mrb, obj, mrb_class_ptr(mod)))
-    return mrb_false_value();
-  return mrb_true_value();
+  eqq = mrb_obj_is_kind_of(mrb, obj, mrb_class_ptr(mod));
+
+  return mrb_true_or_false_value(eqq);
 }
 
 void
diff --git a/src/error.c b/src/error.c
index ddf92382b..e86e3f22c 100644
--- a/src/error.c
+++ b/src/error.c
@@ -160,25 +160,29 @@ exc_equal(mrb_state *mrb, mrb_value exc)
 {
   mrb_value obj;
   mrb_value mesg;
+  mrb_bool equal_p;
   mrb_sym id_mesg = mrb_intern(mrb, "mesg");
 
   mrb_get_args(mrb, "o", &obj);
-  if (mrb_obj_equal(mrb, exc, obj)) return mrb_true_value();
-
-  if (mrb_obj_class(mrb, exc) != mrb_obj_class(mrb, obj)) {
-    if (mrb_respond_to(mrb, obj, mrb_intern(mrb, "message"))) {
-      mesg = mrb_funcall(mrb, obj, "message", 0);
-    }
-    else
-      return mrb_false_value();
+  if (mrb_obj_equal(mrb, exc, obj)) {
+    equal_p = 1;
   }
   else {
-    mesg = mrb_attr_get(mrb, obj, id_mesg);
+    if (mrb_obj_class(mrb, exc) != mrb_obj_class(mrb, obj)) {
+      if (mrb_respond_to(mrb, obj, mrb_intern(mrb, "message"))) {
+        mesg = mrb_funcall(mrb, obj, "message", 0);
+      }
+      else
+        return mrb_false_value();
+    }
+    else {
+      mesg = mrb_attr_get(mrb, obj, id_mesg);
+    }
+
+    equal_p = mrb_equal(mrb, mrb_attr_get(mrb, exc, id_mesg), mesg);
   }
 
-  if (!mrb_equal(mrb, mrb_attr_get(mrb, exc, id_mesg), mesg))
-    return mrb_false_value();
-  return mrb_true_value();
+  return mrb_true_or_false_value(equal_p);
 }
 
 static void
diff --git a/src/gc.c b/src/gc.c
index 2a50cb98c..b7c31223f 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -982,8 +982,8 @@ gc_enable(mrb_state *mrb, mrb_value obj)
   int old = mrb->gc_disabled;
 
   mrb->gc_disabled = FALSE;
-  if (old) return mrb_true_value();
-  return mrb_false_value();
+
+  return mrb_true_or_false_value(old);
 }
 
 /*
@@ -1004,8 +1004,8 @@ gc_disable(mrb_state *mrb, mrb_value obj)
   int old = mrb->gc_disabled;
 
   mrb->gc_disabled = TRUE;
-  if (old) return mrb_true_value();
-  return mrb_false_value();
+
+  return mrb_true_or_false_value(old);
 }
 
 /*
@@ -1101,10 +1101,7 @@ change_gen_gc_mode(mrb_state *mrb, mrb_int enable)
 static mrb_value
 gc_generational_mode_get(mrb_state *mrb, mrb_value self)
 {
-  if (mrb->is_generational_gc_mode)
-    return mrb_true_value();
-  else
-    return mrb_false_value();
+  return mrb_true_or_false_value(mrb->is_generational_gc_mode);
 }
 
 /*
@@ -1124,10 +1121,7 @@ gc_generational_mode_set(mrb_state *mrb, mrb_value self)
   if (mrb->is_generational_gc_mode != enable)
     change_gen_gc_mode(mrb, enable);
 
-  if (enable)
-    return mrb_true_value();
-  else
-    return mrb_false_value();
+  return mrb_true_or_false_value(enable);
 }
 
 #ifdef GC_TEST
diff --git a/src/hash.c b/src/hash.c
index 58f5243cf..2eb1b78ed 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -801,13 +801,16 @@ static mrb_value
 mrb_hash_empty_p(mrb_state *mrb, mrb_value self)
 {
   khash_t(ht) *h = RHASH_TBL(self);
+  mrb_bool empty_p;
 
   if (h) {
-    if (kh_size(h) == 0)
-      return mrb_true_value();
-    return mrb_false_value();
+    empty_p = (kh_size(h) == 0);
   }
-  return mrb_true_value();
+  else {
+    empty_p = 1;
+  }
+
+  return mrb_true_or_false_value(empty_p);
 }
 
 /* 15.2.13.4.11 */
@@ -1010,14 +1013,17 @@ mrb_hash_has_keyWithKey(mrb_state *mrb, mrb_value hash, mrb_value key)
 {
   khash_t(ht) *h = RHASH_TBL(hash);
   khiter_t k;
+  mrb_bool result;
 
   if (h) {
     k = kh_get(ht, h, key);
-    if (k != kh_end(h))
-      return mrb_true_value();
+    result = (k != kh_end(h));
+  }
+  else {
+    result = 0;
   }
 
-  return mrb_false_value();
+  return mrb_true_or_false_value(result);
 }
 
 /* 15.2.13.4.13 */
@@ -1109,8 +1115,7 @@ hash_equal(mrb_state *mrb, mrb_value hash1, mrb_value hash2, int eql)
   h1 = RHASH_TBL(hash1);
   h2 = RHASH_TBL(hash2);
   if (!h1) {
-    if (!h2)  return mrb_true_value();
-    return mrb_false_value();
+    return mrb_true_or_false_value(!h2);
   }
   if (!h2) return mrb_false_value();
   if (kh_size(h1) != kh_size(h2)) return mrb_false_value();
diff --git a/src/kernel.c b/src/kernel.c
index 973339c95..445a0b097 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -96,28 +96,24 @@ static mrb_value
 mrb_obj_equal_m(mrb_state *mrb, mrb_value self)
 {
   mrb_value arg;
+  mrb_bool eql_p;
 
   mrb_get_args(mrb, "o", &arg);
-  if (mrb_obj_equal(mrb, self, arg)) {
-    return mrb_true_value();
-  }
-  else {
-    return mrb_false_value();
-  }
+  eql_p = mrb_obj_equal(mrb, self, arg);
+
+  return mrb_true_or_false_value(eql_p);
 }
 
 static mrb_value
 mrb_obj_not_equal_m(mrb_state *mrb, mrb_value self)
 {
   mrb_value arg;
+  mrb_bool eql_p;
 
   mrb_get_args(mrb, "o", &arg);
-  if (mrb_equal(mrb, self, arg)) {
-    return mrb_false_value();
-  }
-  else {
-    return mrb_true_value();
-  }
+  eql_p = mrb_obj_equal(mrb, self, arg);
+
+  return mrb_true_or_false_value(!eql_p);
 }
 
 /* 15.3.1.3.2  */
@@ -133,14 +129,12 @@ static mrb_value
 mrb_equal_m(mrb_state *mrb, mrb_value self)
 {
   mrb_value arg;
+  mrb_bool equal_p;
 
   mrb_get_args(mrb, "o", &arg);
-  if (mrb_equal(mrb, self, arg)){
-    return mrb_true_value();
-  }
-  else {
-    return mrb_false_value();
-  }
+  equal_p = mrb_equal(mrb, self, arg);
+
+  return mrb_true_or_false_value(equal_p);
 }
 
 /* 15.3.1.3.3  */
@@ -225,21 +219,28 @@ mrb_f_block_given_p_m(mrb_state *mrb, mrb_value self)
 {
   mrb_callinfo *ci = mrb->ci;
   mrb_value *bp;
+  mrb_bool given_p;
 
   bp = mrb->stbase + ci->stackidx + 1;
   ci--;
-  if (ci <= mrb->cibase) return mrb_false_value();
-  /* block_given? called within block; check upper scope */
-  if (ci->proc->env && ci->proc->env->stack) {
-    if (ci->proc->env->stack == mrb->stbase || mrb_nil_p(ci->proc->env->stack[1]))
-      return mrb_false_value();
-    return mrb_true_value();
+  if (ci <= mrb->cibase) {
+    given_p = 0;
   }
-  if (ci->argc > 0) {
-    bp += ci->argc;
+  else {
+    /* block_given? called within block; check upper scope */
+    if (ci->proc->env && ci->proc->env->stack) {
+      given_p = !(ci->proc->env->stack == mrb->stbase ||
+                  mrb_nil_p(ci->proc->env->stack[1]));
+    }
+    else {
+      if (ci->argc > 0) {
+        bp += ci->argc;
+      }
+      given_p = !mrb_nil_p(*bp);
+    }
   }
-  if (mrb_nil_p(*bp)) return mrb_false_value();
-  return mrb_true_value();
+
+  return mrb_true_or_false_value(given_p);
 }
 
 /* 15.3.1.3.7  */
@@ -542,14 +543,12 @@ static mrb_value
 obj_is_instance_of(mrb_state *mrb, mrb_value self)
 {
   mrb_value arg;
+  mrb_bool instance_of_p;
 
   mrb_get_args(mrb, "o", &arg);
-  if (mrb_obj_is_instance_of(mrb, self, mrb_class_ptr(arg))){
-    return mrb_true_value();
-  }
-  else {
-    return mrb_false_value();
-  }
+  instance_of_p = mrb_obj_is_instance_of(mrb, self, mrb_class_ptr(arg));
+
+  return mrb_true_or_false_value(instance_of_p);
 }
 
 static void
@@ -586,12 +585,13 @@ mrb_value
 mrb_obj_ivar_defined(mrb_state *mrb, mrb_value self)
 {
   mrb_sym mid;
+  mrb_bool defined_p;
 
   mrb_get_args(mrb, "n", &mid);
   check_iv_name(mrb, mid);
-  if (mrb_obj_iv_defined(mrb, mrb_obj_ptr(self), mid))
-    return mrb_true_value();
-  return mrb_false_value();
+  defined_p = mrb_obj_iv_defined(mrb, mrb_obj_ptr(self), mid);
+
+  return mrb_true_or_false_value(defined_p);
 }
 
 /* 15.3.1.3.21 */
@@ -688,14 +688,12 @@ mrb_value
 mrb_obj_is_kind_of_m(mrb_state *mrb, mrb_value self)
 {
   mrb_value arg;
+  mrb_bool kind_of_p;
 
   mrb_get_args(mrb, "o", &arg);
-  if (mrb_obj_is_kind_of(mrb, self, mrb_class_ptr(arg))) {
-    return mrb_true_value();
-  }
-  else {
-    return mrb_false_value();
-  }
+  kind_of_p = mrb_obj_is_kind_of(mrb, self, mrb_class_ptr(arg));
+
+  return mrb_true_or_false_value(kind_of_p);
 }
 
 static void
@@ -1002,15 +1000,17 @@ obj_respond_to(mrb_state *mrb, mrb_value self)
   int argc;
   mrb_value mid, priv;
   mrb_sym id;
+  mrb_bool respond_to_p;
 
   mrb_get_args(mrb, "*", &argv, &argc);
   mid = argv[0];
   if (argc > 1) priv = argv[1];
   else priv = mrb_nil_value();
   id = mrb_to_id(mrb, mid);
-  if (basic_obj_respond_to(mrb, self, id, !mrb_test(priv)))
-    return mrb_true_value();
-  return mrb_false_value();
+
+  respond_to_p = basic_obj_respond_to(mrb, self, id, !mrb_test(priv));
+
+  return mrb_true_or_false_value(respond_to_p);
 }
 
 /* 15.3.1.3.45 */
diff --git a/src/numeric.c b/src/numeric.c
index 2cd255a2d..262fa921a 100644
--- a/src/numeric.c
+++ b/src/numeric.c
@@ -380,15 +380,17 @@ static mrb_value
 num_eql(mrb_state *mrb, mrb_value x)
 {
   mrb_value y;
+  mrb_bool eql_p;
 
   mrb_get_args(mrb, "o", &y);
-  if (mrb_type(x) != mrb_type(y)) return mrb_false_value();
-  if (mrb_equal(mrb, x, y)) {
-      return mrb_true_value();
+  if (mrb_type(x) != mrb_type(y)) {
+    eql_p = 0;
   }
   else {
-      return mrb_false_value();
+    eql_p = mrb_equal(mrb, x, y);
   }
+
+  return mrb_true_or_false_value(eql_p);
 }
 
 static mrb_value
@@ -430,7 +432,7 @@ flo_eq(mrb_state *mrb, mrb_value x)
     return num_equal(mrb, x, y);
   }
   a = mrb_float(x);
-  return (a == b)?mrb_true_value():mrb_false_value();
+  return mrb_true_or_false_value(a == b);
 }
 
 /* 15.2.8.3.18 */
@@ -511,10 +513,11 @@ static mrb_value
 flo_finite_p(mrb_state *mrb, mrb_value num)
 {
   mrb_float value = mrb_float(num);
+  mrb_bool finite_p;
+
+  finite_p = !(isinf(value) || isnan(value));
 
-  if (isinf(value) || isnan(value))
-    return mrb_false_value();
-  return mrb_true_value();
+  return mrb_true_or_false_value(finite_p);
 }
 
 /* 15.2.9.3.10 */
@@ -923,19 +926,15 @@ static mrb_value
 fix_equal(mrb_state *mrb, mrb_value x)
 {
   mrb_value y;
+  mrb_bool equal_p;
 
   mrb_get_args(mrb, "o", &y);
 
-  if (mrb_obj_equal(mrb, x, y)) return mrb_true_value();
-  switch (mrb_type(y)) {
-  case MRB_TT_FLOAT:
-    if ((mrb_float)mrb_fixnum(x) == mrb_float(y))
-      return mrb_true_value();
-    /* fall through */
-  case MRB_TT_FIXNUM:
-  default:
-    return mrb_false_value();
-  }
+  equal_p = mrb_obj_equal(mrb, x, y) ||
+      (mrb_type(y) == MRB_TT_FLOAT &&
+       (mrb_float)mrb_fixnum(x) == mrb_float(y));
+
+  return mrb_true_or_false_value(equal_p);
 }
 
 /* 15.2.8.3.8  */
diff --git a/src/object.c b/src/object.c
index fdaf155e5..2e8366335 100644
--- a/src/object.c
+++ b/src/object.c
@@ -114,7 +114,8 @@ true_and(mrb_state *mrb, mrb_value obj)
   int obj2;
 
   mrb_get_args(mrb, "b", &obj2);
-  return obj2 ? mrb_true_value() : mrb_false_value();
+
+  return mrb_true_or_false_value(obj2);
 }
 
 /* 15.2.5.3.2  */
@@ -133,7 +134,7 @@ true_xor(mrb_state *mrb, mrb_value obj)
   int obj2;
 
   mrb_get_args(mrb, "b", &obj2);
-  return obj2 ? mrb_false_value() : mrb_true_value();
+  return mrb_true_or_false_value(!obj2);
 }
 
 /* 15.2.5.3.3  */
@@ -226,7 +227,7 @@ false_xor(mrb_state *mrb, mrb_value obj)
   int obj2;
 
   mrb_get_args(mrb, "b", &obj2);
-  return obj2 ? mrb_true_value() : mrb_false_value();
+  return mrb_true_or_false_value(obj2);
 }
 
 /* 15.2.4.3.3  */
@@ -246,7 +247,7 @@ false_or(mrb_state *mrb, mrb_value obj)
   int obj2;
 
   mrb_get_args(mrb, "b", &obj2);
-  return obj2 ? mrb_true_value() : mrb_false_value();
+  return mrb_true_or_false_value(obj2);
 }
 
 /* 15.2.6.3.3  */
diff --git a/src/range.c b/src/range.c
index 76d494b4f..8d36ed7b4 100644
--- a/src/range.c
+++ b/src/range.c
@@ -91,7 +91,7 @@ mrb_range_excl(mrb_state *mrb, mrb_value range)
 {
   struct RRange *r = mrb_range_ptr(range);
 
-  return r->excl ? mrb_true_value() : mrb_false_value();
+  return mrb_true_or_false_value(r->excl);
 }
 
 static void
@@ -152,25 +152,30 @@ mrb_range_eq(mrb_state *mrb, mrb_value range)
   struct RRange *rr;
   struct RRange *ro;
   mrb_value obj;
+  mrb_bool eq_p;
 
   mrb_get_args(mrb, "o", &obj);
 
-  if (mrb_obj_equal(mrb, range, obj)) return mrb_true_value();
-
-  /* same class? */
-  if (!mrb_obj_is_instance_of(mrb, obj, mrb_obj_class(mrb, range)))
-    return mrb_false_value();
-
-  rr = mrb_range_ptr(range);
-  ro = mrb_range_ptr(obj);
-  if (!mrb_obj_equal(mrb, rr->edges->beg, ro->edges->beg))
-    return mrb_false_value();
-  if (!mrb_obj_equal(mrb, rr->edges->end, ro->edges->end))
-    return mrb_false_value();
-  if (rr->excl != ro->excl)
-    return mrb_false_value();
+  if (mrb_obj_equal(mrb, range, obj)) {
+    eq_p = 1;
+  }
+  else if (!mrb_obj_is_instance_of(mrb, obj, mrb_obj_class(mrb, range))) { /* same class? */
+    eq_p = 0;
+  }
+  else {
+    rr = mrb_range_ptr(range);
+    ro = mrb_range_ptr(obj);
+    if (!mrb_obj_equal(mrb, rr->edges->beg, ro->edges->beg) ||
+        !mrb_obj_equal(mrb, rr->edges->end, ro->edges->end) ||
+        rr->excl != ro->excl) {
+      eq_p = 0;
+    }
+    else {
+      eq_p = 1;
+    }
+  }
 
-  return mrb_true_value();
+  return mrb_true_or_false_value(eq_p);
 }
 
 static int
@@ -227,21 +232,17 @@ mrb_range_include(mrb_state *mrb, mrb_value range)
   mrb_value val;
   struct RRange *r = mrb_range_ptr(range);
   mrb_value beg, end;
+  mrb_bool include_p;
 
   mrb_get_args(mrb, "o", &val);
 
   beg = r->edges->beg;
   end = r->edges->end;
-  if (r_le(mrb, beg, val)) {
-    /* beg <= val */
-    if (r->excl) {
-      if (r_gt(mrb, end, val)) return mrb_true_value(); /* end >  val */
-    }
-    else {
-      if (r_ge(mrb, end, val)) return mrb_true_value(); /* end >= val */
-    }
-  }
-  return mrb_false_value();
+  include_p = r_le(mrb, beg, val) && /* beg <= val */
+              ((r->excl && r_gt(mrb, end, val)) || /* end >  val */
+              (r_ge(mrb, end, val))); /* end >= val */
+
+  return mrb_true_or_false_value(include_p);
 }
 
 /*
@@ -384,23 +385,34 @@ range_eql(mrb_state *mrb, mrb_value range)
 {
   mrb_value obj;
   struct RRange *r, *o;
+  mrb_bool eql_p;
 
   mrb_get_args(mrb, "o", &obj);
-  if (mrb_obj_equal(mrb, range, obj))
-    return mrb_true_value();
-  if (!mrb_obj_is_kind_of(mrb, obj, RANGE_CLASS))
-    return mrb_false_value();
-
-  r = mrb_range_ptr(range);
-  if (mrb_type(obj) != MRB_TT_RANGE) return mrb_false_value();
-  o = mrb_range_ptr(obj);
-  if (!mrb_eql(mrb, r->edges->beg, o->edges->beg))
-    return mrb_false_value();
-  if (!mrb_eql(mrb, r->edges->end, o->edges->end))
-    return mrb_false_value();
-  if (r->excl != o->excl)
-    return mrb_false_value();
-  return mrb_true_value();
+  if (mrb_obj_equal(mrb, range, obj)) {
+    eql_p = 1;
+  }
+  else if (!mrb_obj_is_kind_of(mrb, obj, RANGE_CLASS)) {
+    eql_p = 0;
+  }
+  else {
+    r = mrb_range_ptr(range);
+    if (mrb_type(obj) != MRB_TT_RANGE) {
+      eql_p = 0;
+    }
+    else {
+      o = mrb_range_ptr(obj);
+      if (!mrb_eql(mrb, r->edges->beg, o->edges->beg) ||
+          !mrb_eql(mrb, r->edges->end, o->edges->end) ||
+          (r->excl != o->excl)) {
+        eql_p = 0;
+      }
+      else {
+        eql_p = 1;
+      }
+    }
+  }
+
+  return mrb_true_or_false_value(eql_p);
 }
 
 /* 15.2.14.4.15(x) */
diff --git a/src/string.c b/src/string.c
index 7fefbefb5..41f2e5a06 100644
--- a/src/string.c
+++ b/src/string.c
@@ -596,11 +596,12 @@ static mrb_value
 mrb_str_equal_m(mrb_state *mrb, mrb_value str1)
 {
   mrb_value str2;
+  mrb_bool equal_p;
 
   mrb_get_args(mrb, "o", &str2);
-  if (mrb_str_equal(mrb, str1, str2))
-    return mrb_true_value();
-  return mrb_false_value();
+  equal_p = mrb_str_equal(mrb, str1, str2);
+
+  return mrb_true_or_false_value(equal_p);
 }
 /* ---------------------------------- */
 mrb_value
@@ -1134,9 +1135,7 @@ mrb_str_empty_p(mrb_state *mrb, mrb_value self)
 {
   struct RString *s = mrb_str_ptr(self);
 
-  if (s->len == 0)
-    return mrb_true_value();
-  return mrb_false_value();
+  return mrb_true_or_false_value(s->len == 0);
 }
 
 /* 15.2.10.5.17 */
@@ -1150,13 +1149,12 @@ static mrb_value
 mrb_str_eql(mrb_state *mrb, mrb_value self)
 {
   mrb_value str2;
+  mrb_bool eql_p;
 
   mrb_get_args(mrb, "o", &str2);
-  if (mrb_type(str2) != MRB_TT_STRING)
-    return mrb_false_value();
-  if (str_eql(mrb, self, str2))
-    return mrb_true_value();
-  return mrb_false_value();
+  eql_p = (mrb_type(str2) == MRB_TT_STRING) && str_eql(mrb, self, str2);
+
+  return mrb_true_or_false_value(eql_p);
 }
 
 static mrb_value
@@ -1314,18 +1312,20 @@ mrb_str_include(mrb_state *mrb, mrb_value self)
 {
   mrb_int i;
   mrb_value str2;
+  mrb_bool include_p;
 
   mrb_get_args(mrb, "o", &str2);
   if (mrb_type(str2) == MRB_TT_FIXNUM) {
-    if (memchr(RSTRING_PTR(self), mrb_fixnum(str2), RSTRING_LEN(self)))
-      return mrb_true_value();
-    return mrb_false_value();
+    include_p = memchr(RSTRING_PTR(self), mrb_fixnum(str2), RSTRING_LEN(self));
+  }
+  else {
+    mrb_string_value(mrb, &str2);
+    i = mrb_str_index(mrb, self, str2, 0);
+
+    include_p = (i != -1);
   }
-  mrb_string_value(mrb, &str2);
-  i = mrb_str_index(mrb, self, str2, 0);
 
-  if (i == -1) return mrb_false_value();
-  return mrb_true_value();
+  return mrb_true_or_false_value(include_p);
 }
 
 /* 15.2.10.5.22 */
diff --git a/src/symbol.c b/src/symbol.c
index 1c56af4cf..a67ad7418 100644
--- a/src/symbol.c
+++ b/src/symbol.c
@@ -158,10 +158,12 @@ static mrb_value
 sym_equal(mrb_state *mrb, mrb_value sym1)
 {
   mrb_value sym2;
+  mrb_bool equal_p;
 
   mrb_get_args(mrb, "o", &sym2);
-  if (mrb_obj_equal(mrb, sym1, sym2)) return mrb_true_value();
-  return mrb_false_value();
+  equal_p = mrb_obj_equal(mrb, sym1, sym2);
+
+  return mrb_true_or_false_value(equal_p);
 }
 
 /* 15.2.11.3.2  */