refactor: Rework

src/prolog/ast/terms/Term.kt

@@ -1,16 +1,13 @@
 package prolog.ast.terms
 
-import prolog.logic.Substituted
+import prolog.logic.compare
 
 /**
  * Value in Prolog.
  *
- * A [Term] is either a [Variable], [Atom], integer, float or [CompoundTerm].
+ * A [Term] is either a [Variable], [Atom], [Integer], float or [CompoundTerm].
  * In addition, SWI-Prolog also defines the type string.
  */
 interface Term : Comparable<Term> {
-    /**
-     * Returns the term that this expression evaluates to. (All the way down.)
-     */
-    fun evaluate(subs: Substituted): Pair<Term, Substituted>
+    override fun compareTo(other: Term): Int = compare(this, other, emptyMap())
 }