re-apply 3644f1ba since we have fixed GC bug

mrblib/compar.rb

@@ -14,11 +14,8 @@ module Comparable
     cmp = self <=> other
     if cmp.nil?
       raise ArgumentError, "comparison of #{self.class} with #{other.class} failed"
-    elsif cmp < 0
-      true
-    else
-      false
     end
+    cmp < 0
   end
 
   ##
@@ -31,11 +28,8 @@ module Comparable
     cmp = self <=> other
     if cmp.nil?
       raise ArgumentError, "comparison of #{self.class} with #{other.class} failed"
-    elsif cmp <= 0
-      true
-    else
-      false
     end
+    cmp <= 0
   end
 
   ##
@@ -46,11 +40,7 @@ module Comparable
   # ISO 15.3.3.2.3
   def == other
     cmp = self <=> other
-    if cmp == 0
-      true
-    else
-      false
-    end
+    cmp == 0
   end
 
   ##
@@ -63,11 +53,8 @@ module Comparable
     cmp = self <=> other
     if cmp.nil?
       raise ArgumentError, "comparison of #{self.class} with #{other.class} failed"
-    elsif cmp > 0
-      true
-    else
-      false
     end
+    cmp > 0
   end
 
   ##
@@ -80,11 +67,8 @@ module Comparable
     cmp = self <=> other
     if cmp.nil?
       raise ArgumentError, "comparison of #{self.class} with #{other.class} failed"
-    elsif cmp >= 0
-      true
-    else
-      false
     end
+    cmp >= 0
   end
 
   ##
@@ -95,10 +79,6 @@ module Comparable
   #
   # ISO 15.3.3.2.6
   def between?(min, max)
-    if self < min or self > max
-      false
-    else
-      true
-    end
+    self >= min and self <= max
   end
 end