Checkpoint

src/prolog/builtins/io.kt

@@ -4,6 +4,7 @@ import io.Logger
 import io.Terminal
 import parser.ReplParser
 import prolog.Answers
+import prolog.Program
 import prolog.Substitutions
 import prolog.ast.logic.Satisfiable
 import prolog.ast.terms.Atom
@@ -21,6 +22,8 @@ class Write(private val term: Term) : Operator(Atom("write"), null, term), Satis
 
         Terminal().say(t.toString())
 
+        Program.storeNewLine = true
+
         return sequenceOf(Result.success(emptyMap()))
     }
 }
@@ -31,6 +34,7 @@ class Write(private val term: Term) : Operator(Atom("write"), null, term), Satis
 object Nl : Atom("nl"), Satisfiable {
     override fun satisfy(subs: Substitutions): Answers {
         Terminal().say("\n")
+        Program.storeNewLine = false
         return sequenceOf(Result.success(emptyMap()))
     }
 }

src/prolog/builtins/other.kt

@@ -6,6 +6,10 @@ import prolog.ast.logic.LogicOperand
 import prolog.ast.terms.Atom
 import prolog.ast.logic.LogicOperator
 
+class Initialization(val goal: LogicOperand) : LogicOperator(Atom(":-"), null, goal) {
+    override fun satisfy(subs: Substitutions): Answers = goal.satisfy(subs).take(1)
+}
+
 class Query(val query: LogicOperand) : LogicOperator(Atom("?-"), null, query) {
     override fun satisfy(subs: Substitutions): Answers = query.satisfy(subs)
 }

src/prolog/builtins/unificationOperators.kt

@@ -26,6 +26,11 @@ class Unify(private val term1: Term, private val term2: Term): Operator(Atom("="
     }
 }
 
+class NotUnify(term1: Term, term2: Term) : Operator(Atom("\\="), term1, term2) {
+    private val not = Not(Unify(term1, term2))
+    override fun satisfy(subs: Substitutions): Answers = not.satisfy(subs)
+}
+
 class Equivalent(private val term1: Term, private val term2: Term) : Operator(Atom("=="), term1, term2) {
     override fun satisfy(subs: Substitutions): Answers = sequence {
         val t1 = applySubstitution(term1, subs)