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/* 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.
*/
#pragma once
#include "RuleContext.h"
#include "support/CPPUtils.h"
namespace antlr4 {
/// <summary>
/// A rule invocation record for parsing.
///
/// Contains all of the information about the current rule not stored in the
/// RuleContext. It handles parse tree children list, Any ATN state
/// tracing, and the default values available for rule invocatons:
/// start, stop, rule index, current alt number.
///
/// Subclasses made for each rule and grammar track the parameters,
/// return values, locals, and labels specific to that rule. These
/// are the objects that are returned from rules.
///
/// Note text is not an actual field of a rule return value; it is computed
/// from start and stop using the input stream's toString() method. I
/// could add a ctor to this so that we can pass in and store the input
/// stream, but I'm not sure we want to do that. It would seem to be undefined
/// to get the .text property anyway if the rule matches tokens from multiple
/// input streams.
///
/// I do not use getters for fields of objects that are used simply to
/// group values such as this aggregate. The getters/setters are there to
/// satisfy the superclass interface.
/// </summary>
class ANTLR4CPP_PUBLIC ParserRuleContext : public RuleContext {
public:
static ParserRuleContext EMPTY;
/// <summary>
/// For debugging/tracing purposes, we want to track all of the nodes in
/// the ATN traversed by the parser for a particular rule.
/// This list indicates the sequence of ATN nodes used to match
/// the elements of the children list. This list does not include
/// ATN nodes and other rules used to match rule invocations. It
/// traces the rule invocation node itself but nothing inside that
/// other rule's ATN submachine.
///
/// There is NOT a one-to-one correspondence between the children and
/// states list. There are typically many nodes in the ATN traversed
/// for each element in the children list. For example, for a rule
/// invocation there is the invoking state and the following state.
///
/// The parser setState() method updates field s and adds it to this list
/// if we are debugging/tracing.
///
/// This does not trace states visited during prediction.
/// </summary>
// public List<Integer> states;
Token *start;
Token *stop;
/// The exception that forced this rule to return. If the rule successfully
/// completed, this is "null exception pointer".
std::exception_ptr exception;
ParserRuleContext();
ParserRuleContext(ParserRuleContext *parent, size_t invokingStateNumber);
/** COPY a ctx (I'm deliberately not using copy constructor) to avoid
* confusion with creating node with parent. Does not copy children
* (except error leaves).
*/
virtual void copyFrom(ParserRuleContext *ctx);
// Double dispatch methods for listeners
virtual void enterRule(tree::ParseTreeListener *listener);
virtual void exitRule(tree::ParseTreeListener *listener);
/** Add a token leaf node child and force its parent to be this node. */
tree::TerminalNode* addChild(tree::TerminalNode *t);
RuleContext* addChild(RuleContext *ruleInvocation);
/// Used by enterOuterAlt to toss out a RuleContext previously added as
/// we entered a rule. If we have # label, we will need to remove
/// generic ruleContext object.
void removeLastChild();
tree::TerminalNode* getToken(size_t ttype, std::size_t i) const;
std::vector<tree::TerminalNode*> getTokens(size_t ttype) const;
template<typename T>
T* getRuleContext(size_t i) const {
static_assert(std::is_base_of_v<RuleContext, T>, "T must be derived from RuleContext");
size_t j = 0; // what element have we found with ctxType?
for (auto *child : children) {
if (RuleContext::is(child)) {
if (auto *typedChild = dynamic_cast<T*>(child); typedChild != nullptr) {
if (j++ == i) {
return typedChild;
}
}
}
}
return nullptr;
}
template<typename T>
std::vector<T*> getRuleContexts() const {
static_assert(std::is_base_of_v<RuleContext, T>, "T must be derived from RuleContext");
std::vector<T*> contexts;
for (auto *child : children) {
if (RuleContext::is(child)) {
if (auto *typedChild = dynamic_cast<T*>(child); typedChild != nullptr) {
contexts.push_back(typedChild);
}
}
}
return contexts;
}
virtual misc::Interval getSourceInterval() override;
/**
* Get the initial token in this context.
* Note that the range from start to stop is inclusive, so for rules that do not consume anything
* (for example, zero length or error productions) this token may exceed stop.
*/
Token* getStart() const;
/**
* Get the final token in this context.
* Note that the range from start to stop is inclusive, so for rules that do not consume anything
* (for example, zero length or error productions) this token may precede start.
*/
Token* getStop() const;
/// <summary>
/// Used for rule context info debugging during parse-time, not so much for ATN debugging </summary>
virtual std::string toInfoString(Parser *recognizer);
};
} // namespace antlr4