feat: Atom parsing

src/prolog/ast/terms/Atom.kt

@@ -13,4 +13,12 @@ open class Atom(val name: String) : Goal(), Head, Body, Resolvent {
     override fun toString(): String {
         return name
     }
+
+    override fun equals(other: Any?): Boolean {
+        return (this === other) || (other is Atom && functor == other.functor)
+    }
+
+    override fun hashCode(): Int {
+        return javaClass.hashCode()
+    }
 }