package com.jclark.xsl.expr;

import com.jclark.xsl.om.*;

abstract class ConvertibleStringExpr extends ConvertibleExpr implements StringExpr {

  ConvertibleStringExpr makeStringExpr() {
    return this;
  }

  ConvertibleBooleanExpr makeBooleanExpr() {
    return new ConvertibleBooleanExpr() {
      public boolean eval(Node node, ExprContext context) throws XSLException {
	return Converter.toBoolean(ConvertibleStringExpr.this.eval(node, context));
      }
    };
  }

  ConvertibleVariantExpr makeVariantExpr() {
    return new ConvertibleVariantExpr() {
      public Variant eval(Node node, ExprContext context) throws XSLException {
	return new StringVariant(ConvertibleStringExpr.this.eval(node, context));
      }
    };
  }

  ConvertibleNumberExpr makeNumberExpr() {
    return new ConvertibleNumberExpr() {
      public double eval(Node node, ExprContext context) throws XSLException {
	return Converter.toNumber(ConvertibleStringExpr.this.eval(node, context));
      }
    };
  }

  public String constantValue() {
    return null;
  }
}