[types] Add Bools to the mix

types/src/bool.rs

@@ -2,14 +2,19 @@
  * Eryn Wells <eryn@erynwells.me>
  */
 
+use std::any::Any;
 use std::fmt;
-use object::Obj;
-use preds;
+use std::ops::Deref;
+use object::{Obj, Object};
 
 /// The Scheme boolean type. It can be `True` or `False`.
+#[derive(Debug, PartialEq)]
 pub enum Bool { True, False }
 
-impl Obj for Bool { }
+impl Object for Bool {
+    fn as_any(&self) -> &Any { self }
+    fn as_bool(&self) -> Option<&Bool> { Some(self) }
+}
 
 impl fmt::Display for Bool {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -20,25 +25,29 @@ impl fmt::Display for Bool {
     }
 }
 
-impl preds::IsBool for Bool {
-    fn is_bool(&self) -> bool { true }
+impl PartialEq<Obj> for Bool {
+    fn eq(&self, rhs: &Obj) -> bool {
+        match rhs {
+            Obj::Null => false,
+            Obj::Ptr(ref inner) => {
+                if let Some(rhs_bool) = inner.deref().as_bool() {
+                    self == rhs_bool
+                } else {
+                    false
+                }
+            }
+        }
+    }
 }
 
 #[cfg(test)]
 mod tests {
-    use object::Object;
-    use predicates::{IsBool, IsChar};
-
-    #[test]
-    fn bools_are_bools() {
-        assert_eq!(Object::Bool(false).is_bool(), true);
-        assert_eq!(Object::Bool(false).is_char(), false);
-    }
+    use super::Bool;
 
     #[test]
     fn equal_bools_are_equal() {
-        assert_eq!(Object::Bool(true), Object::Bool(true));
-        assert_eq!(Object::Bool(false), Object::Bool(false));
-        assert_ne!(Object::Bool(true), Object::Bool(false));
+        assert_eq!(Bool::True, Bool::True);
+        assert_eq!(Bool::False, Bool::False);
+        assert_ne!(Bool::True, Bool::False);
     }
 }

types/src/lib.rs

@@ -1,7 +1,9 @@
+mod bool;
 mod object;
 mod pair;
 mod sym;
 
+pub use bool::Bool;
 pub use object::Obj;
 pub use pair::Pair;
 pub use sym::Sym;

types/src/object.rs

@@ -32,6 +32,8 @@ pub trait Object:
 {
     /// Cast this Object to an Any.
     fn as_any(&self) -> &Any;
+    /// Cast this Object to a Bool if possible.
+    fn as_bool(&self) -> Option<&Bool> { None }
     /// Cast this Object to a Pair if possible.
     fn as_pair(&self) -> Option<&Pair> { None }
     /// Cast this Object to a Sym if possible.