/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

package org.antlr.v4.tool;

import org.antlr.v4.tool.ast.ActionAST;

Grammars, rules, and alternatives all have symbols visible to
 actions.  To evaluate attr exprs, ask action for its resolver
 then ask resolver to look up various symbols. Depending on the context,
 some symbols are available at some aren't.
 Alternative level:
 $x		Attribute: rule arguments, return values, predefined rule prop.
			AttributeDict: references to tokens and token labels in the
			current alt (including any elements within subrules contained
			in that outermost alt). x can be rule with scope or a global scope.
			List label: x is a token/rule list label.
 $x.y	Attribute: x is surrounding rule, rule/token/label ref
 $s::y	Attribute: s is any rule with scope or global scope; y is prop within
 Rule level:
 $x		Attribute: rule arguments, return values, predefined rule prop.
			AttributeDict: references to token labels in *any* alt. x can
			be any rule with scope or global scope.
			List label: x is a token/rule list label.
 $x.y	Attribute: x is surrounding rule, label ref (in any alts)
 $s::y	Attribute: s is any rule with scope or global scope; y is prop within
 Grammar level:
 $s		AttributeDict: s is a global scope
 $s::y	Attribute: s is a global scope; y is prop within
/** Grammars, rules, and alternatives all have symbols visible to
 *  actions.  To evaluate attr exprs, ask action for its resolver
 *  then ask resolver to look up various symbols. Depending on the context,
 *  some symbols are available at some aren't.
 *
 *  Alternative level:
 *
 *  $x		Attribute: rule arguments, return values, predefined rule prop.
 * 			AttributeDict: references to tokens and token labels in the
 * 			current alt (including any elements within subrules contained
 * 			in that outermost alt). x can be rule with scope or a global scope.
 * 			List label: x is a token/rule list label.
 *  $x.y	Attribute: x is surrounding rule, rule/token/label ref
 *  $s::y	Attribute: s is any rule with scope or global scope; y is prop within
 *
 *  Rule level:
 *
 *  $x		Attribute: rule arguments, return values, predefined rule prop.
 * 			AttributeDict: references to token labels in *any* alt. x can
 * 			be any rule with scope or global scope.
 * 			List label: x is a token/rule list label.
 *  $x.y	Attribute: x is surrounding rule, label ref (in any alts)
 *  $s::y	Attribute: s is any rule with scope or global scope; y is prop within
 *
 *  Grammar level:
 *
 *  $s		AttributeDict: s is a global scope
 *  $s::y	Attribute: s is a global scope; y is prop within
 */
public interface AttributeResolver {
	public boolean resolvesToListLabel(String x, ActionAST node);
	public boolean resolvesToLabel(String x, ActionAST node);
	public boolean resolvesToAttributeDict(String x, ActionAST node);
	public boolean resolvesToToken(String x, ActionAST node);
	public Attribute resolveToAttribute(String x, ActionAST node);
	public Attribute resolveToAttribute(String x, String y, ActionAST node);
}