package com.jclark.xsl.expr;

import com.jclark.xsl.om.*;

class WithCurrentExpr extends ConvertibleExpr {
  private final ConvertibleExpr expr;

  class Context extends DelegateExprContext {
    Node node;

    Context(Node node, ExprContext context) {
      super(context);
      this.node = node;
    }

    public Node getCurrent(Node contextNode) {
      return node;
    }
  }

  WithCurrentExpr(ConvertibleExpr expr) {
    this.expr = expr;
  }

  ConvertibleStringExpr makeStringExpr() {
    final StringExpr e = expr.makeStringExpr();
    return new ConvertibleStringExpr() {
      public String eval(Node node, ExprContext context) throws XSLException {
	return e.eval(node, new Context(node, context));
      }
      public String constantValue() {
	return e.constantValue();
      }
    };
  }

  ConvertibleVariantExpr makeVariantExpr() {
    final VariantExpr e = expr.makeVariantExpr();
    return new ConvertibleVariantExpr() {
      public Variant eval(Node node, ExprContext context) throws XSLException {
	return e.eval(node, new Context(node, context));
      }
    };
  }

  ConvertibleNodeSetExpr makeNodeSetExpr() throws ParseException {
    final NodeSetExpr e = expr.makeNodeSetExpr();
    return new ConvertibleNodeSetExpr() {
      public NodeIterator eval(Node node, ExprContext context) throws XSLException {
	return e.eval(node, new Context(node, context));
      }
    };
  }

  ConvertibleNumberExpr makeNumberExpr() {
    final NumberExpr e = expr.makeNumberExpr();
    return new ConvertibleNumberExpr() {
      public double eval(Node node, ExprContext context) throws XSLException {
	return e.eval(node, new Context(node, context));
      }
    };
  }

  ConvertibleBooleanExpr makeBooleanExpr() {
    final BooleanExpr e = expr.makeBooleanExpr();
    return new ConvertibleBooleanExpr() {
      public boolean eval(Node node, ExprContext context) throws XSLException {
	return e.eval(node, new Context(node, context));
      }
    };
  }
}