Checkpoint

src/parser/grammars/TermsGrammar.kt

@@ -5,8 +5,11 @@ import com.github.h0tk3y.betterParse.grammar.parser
 import com.github.h0tk3y.betterParse.parser.Parser
 import prolog.ast.arithmetic.Float
 import prolog.ast.arithmetic.Integer
+import prolog.ast.lists.List
 import prolog.ast.terms.*
 import prolog.builtins.Dynamic
+import prolog.ast.lists.List.Empty
+import prolog.ast.lists.List.Cons
 
 /**
  * Precedence is based on the following table:
@@ -65,6 +68,7 @@ open class TermsGrammar : Tokens() {
     // Base terms (atoms, compounds, variables, numbers)
     protected val baseTerm: Parser<Term> by (dummy
             or (-leftParenthesis * parser(::term) * -rightParenthesis)
+            or parser(::list)
             or compound
             or atom
             or variable
@@ -112,6 +116,20 @@ open class TermsGrammar : Tokens() {
         t2.fold(t1) { acc, (op, term) -> CompoundTerm(Atom(op), listOf(acc, term)) }
     }
 
+    // Lists
+    protected val list: Parser<List> by (-leftBracket * separated(
+        parser(::termNoConjunction),
+        comma,
+        acceptZero = true
+    ) * -rightBracket) use {
+        var list: List = Empty
+        // Construct the list in reverse order
+        for (term in this.terms.reversed()) {
+            list = Cons(term, list)
+        }
+        list
+    }
+
     // Term - highest level expression
     protected val term: Parser<Term> by term1200
     protected val termNoConjunction: Parser<Term> by term700

src/parser/grammars/Tokens.kt

@@ -10,6 +10,8 @@ import com.github.h0tk3y.betterParse.lexer.token
 abstract class Tokens : Grammar<Any>() {
     protected val leftParenthesis: Token by literalToken("(")
     protected val rightParenthesis: Token by literalToken(")")
+    protected val leftBracket: Token by literalToken("[")
+    protected val rightBracket: Token by literalToken("]")
     protected val exclamation: Token by literalToken("!")
     // 1200
     protected val neck by literalToken(":-")