diff --git a/src/interpreter/Preprocessor.kt b/src/interpreter/Preprocessor.kt
index 97edd8f..c65efd5 100644
--- a/src/interpreter/Preprocessor.kt
+++ b/src/interpreter/Preprocessor.kt
@@ -63,8 +63,6 @@ open class Preprocessor {
                     Functor.of("functor/3") -> FunctorOp(args[0], args[1], args[2])
                     Functor.of("arg/3") -> Arg(args[0], args[1], args[2])
                     Functor.of("clause/2") -> ClauseOp(args[0] as Head, args[1] as Body)
-                    Functor.of("atomic/1") -> AtomicOp(args[0])
-                    Functor.of("compound/1") -> CompoundOp(args[0])
 
                     // Arithmetic
                     Functor.of("inf/0") -> Integer(Int.MAX_VALUE)
@@ -113,6 +111,7 @@ open class Preprocessor {
                     Functor.of("!/0") -> Cut()
                     Functor.of(",/2") -> Conjunction(args[0] as LogicOperand, args[1] as LogicOperand)
                     Functor.of(";/2") -> Disjunction(args[0] as LogicOperand, args[1] as LogicOperand)
+                    Functor.of("|/2") -> Bar(args[0] as LogicOperand, args[1] as LogicOperand)
                     Functor.of("\\+/1") -> Not(args[0] as Goal)
 
                     // Database
diff --git a/src/prolog/builtins/analysisOperators.kt b/src/prolog/builtins/analysisOperators.kt
index 4aff69e..8982313 100644
--- a/src/prolog/builtins/analysisOperators.kt
+++ b/src/prolog/builtins/analysisOperators.kt
@@ -137,23 +137,3 @@ class ClauseOp(private val head: Head, private val body: Body) :
         }
     }
 }
-
-class AtomicOp(private val term: Term) : Operator(Atom("atomic"), null, term) {
-    override fun satisfy(subs: Substitutions): Answers {
-        return if (atomic(term, subs)) {
-            sequenceOf(Result.success(emptyMap()))
-        } else {
-            emptySequence()
-        }
-    }
-}
-
-class CompoundOp(private val term: Term) : Operator(Atom("compound"), null, term) {
-    override fun satisfy(subs: Substitutions): Answers {
-        return if (compound(term, subs)) {
-            sequenceOf(Result.success(emptyMap()))
-        } else {
-            emptySequence()
-        }
-    }
-}
diff --git a/src/repl/Repl.kt b/src/repl/Repl.kt
index 32326ba..4db4fbc 100644
--- a/src/repl/Repl.kt
+++ b/src/repl/Repl.kt
@@ -55,14 +55,7 @@ class Repl {
                     }
                 }
 
-                "" -> {
-                    io.checkNewLine()
-                    return
-                }
-                "a" -> {
-                    io.checkNewLine()
-                    return
-                }
+                "a" -> return
                 "." -> {
                     io.checkNewLine()
                     return