/** Our internal representation of a Paren
 * in the E0 language.
 * See http://www.radford.edu/itec380/2024spring-ibarland/Homeworks/Project/
 * 
 * @author Ian Barland
 * @version 2024.Apr.03
 */

public record Paren(Expr e) implements Expr {

  static final String START_TOKEN = "(";
  static final String STOP_TOKEN  = ")";

  
  @Override
  public String toString(/* Paren this */) {
    return START_TOKEN 
         + this.e.toString()
         + STOP_TOKEN
         ;
    }
    
  /** “@Override” {@link Expr#parse} */
  public static Paren parse( java.util.Scanner s, String punctuation ) {
      UtilIan.verifyToken( UtilIan.nextSplittingBy(s,punctuation), START_TOKEN); // Consume the opening '(', and continue.
      
      // NOTE: recur with `Expr.parse` -- not `parse` = `Paren.parse` which is NOT what we want!
      Expr theInsideExpr = Expr.parse(s,punctuation);
      
      UtilIan.verifyToken( UtilIan.nextSplittingBy(s,punctuation), STOP_TOKEN);   // Consume the closing ')', and continue. 
      return new Paren(theInsideExpr);
      }
      
      
  public Value eval() {
    return this.e.eval();
    }
    
    
  }