Name.java

package calculator.interpreter.ast.vars;

import net.sf.etl.parsers.LiteralUtils;
import calculator.interpreter.Environment;
import calculator.interpreter.EvalException;
import calculator.interpreter.ast.Expression;

/** The name expression (refers to some variable) */
public class Name extends Expression {
  /** The name to resolve (identifier form), use {@link #name()} instead. */
  public String literal;
  /** The name to resolve (quoted form), use {@link #name()} instead. */
  public String quoted;
  /** The parsed name */
  private String parsed;

  /**
   * @return the parsed name
   */
  public String name() {
    if (parsed == null) {
      assert (literal != null) != (quoted != null) : "Exactly one form "
          + "should be specified: q=" + quoted + " l=" + literal;
      if (quoted != null) {
        try {
          parsed = LiteralUtils.parseString(quoted);
        } catch (Exception e) {
          throw new EvalException(this, "The name is invalid format: " + quoted);
        }
      } else {
        parsed = literal;
      }
    }
    return parsed;
  }

  @Override
  public Object eval(Environment env) {
    return env.findDefined(location, name()).get(this);
  }
}