Package org.antlr.v4.runtime
Class ParserRuleContext
java.lang.Object
org.antlr.v4.runtime.RuleContext
org.antlr.v4.runtime.ParserRuleContext
- All Implemented Interfaces:
ParseTree
,RuleNode
,SyntaxTree
,Tree
- Direct Known Subclasses:
InterpreterRuleContext
,RuleContextWithAltNum
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 invocations:
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.
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Field Summary
FieldsModifier and TypeFieldDescriptionIf we are debugging or building a parse tree for a visitor, we need to track all of the tokens and rule invocations associated with this rule's context.static final ParserRuleContext
The exception that forced this rule to return.For debugging/tracing purposes, we want to track all of the nodes in the ATN traversed by the parser for a particular rule.For debugging/tracing purposes, we want to track all of the nodes in the ATN traversed by the parser for a particular rule.Fields inherited from class org.antlr.v4.runtime.RuleContext
invokingState, parent
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescription<T extends ParseTree>
TaddAnyChild
(T t) Add a parse tree node to this as a child.addChild
(RuleContext ruleInvocation) Deprecated.Add a token leaf node child and force its parent to be this node.addErrorNode
(Token badToken) Deprecated.addErrorNode
(ErrorNode errorNode) Add an error node child and force its parent to be this node.void
COPY a ctx (I'm deliberately not using copy constructor) to avoid confusion with creating node with parent.void
enterRule
(ParseTreeListener listener) void
exitRule
(ParseTreeListener listener) getChild
(int i) If there are children, get thei
th value indexed from 0.<T extends ParseTree>
Tint
How many children are there? If there is none, then this node represents a leaf node.The parent of this node.<T extends ParserRuleContext>
TgetRuleContext
(Class<? extends T> ctxType, int i) <T extends ParserRuleContext>
List<T> getRuleContexts
(Class<? extends T> ctxType) Return anInterval
indicating the index in theTokenStream
of the first and last token associated with this subtree.getStart()
Get the initial token in this context.getStop()
Get the final token in this context.getToken
(int ttype, int i) getTokens
(int ttype) void
Used by enterOuterAlt to toss out a RuleContext previously added as we entered a rule.toInfoString
(Parser recognizer) Used for rule context info debugging during parse-time, not so much for ATN debuggingMethods inherited from class org.antlr.v4.runtime.RuleContext
accept, depth, getAltNumber, getPayload, getRuleContext, getRuleIndex, getText, isEmpty, setAltNumber, setParent, toString, toString, toString, toString, toString, toStringTree, toStringTree, toStringTree
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Field Details
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EMPTY
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children
If we are debugging or building a parse tree for a visitor, we need to track all of the tokens and rule invocations associated with this rule's context. This is empty for parsing w/o tree constr. operation because we don't the need to track the details about how we parse this rule. -
start
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. -
stop
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. -
exception
The exception that forced this rule to return. If the rule successfully completed, this isnull
.
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Constructor Details
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ParserRuleContext
public ParserRuleContext() -
ParserRuleContext
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Method Details
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copyFrom
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). This is used in the generated parser code to flip a generic XContext node for rule X to a YContext for alt label Y. In that sense, it is not really a generic copy function. If we do an error sync() at start of a rule, we might add error nodes to the generic XContext so this function must copy those nodes to the YContext as well else they are lost! -
enterRule
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exitRule
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addAnyChild
Add a parse tree node to this as a child. Works for internal and leaf nodes. Does not set parent link; other add methods must do that. Other addChild methods call this. We cannot set the parent pointer of the incoming node because the existing interfaces do not have a setParent() method and I don't want to break backward compatibility for this.- Since:
- 4.7
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addChild
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addChild
Add a token leaf node child and force its parent to be this node. -
addErrorNode
Add an error node child and force its parent to be this node.- Since:
- 4.7
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addChild
Deprecated.Add a child to this node based upon matchedToken. It creates a TerminalNodeImpl rather than usingParser.createTerminalNode(ParserRuleContext, Token)
. I'm leaving this in for compatibility but the parser doesn't use this anymore. -
addErrorNode
Deprecated.Add a child to this node based upon badToken. It creates a ErrorNodeImpl rather than usingParser.createErrorNode(ParserRuleContext, Token)
. I'm leaving this in for compatibility but the parser doesn't use this anymore. -
removeLastChild
public void removeLastChild()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. -
getParent
Description copied from interface:Tree
The parent of this node. If the return value is null, then this node is the root of the tree. -
getChild
Description copied from interface:Tree
If there are children, get thei
th value indexed from 0. -
getChild
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getToken
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getTokens
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getRuleContext
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getRuleContexts
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getChildCount
public int getChildCount()Description copied from interface:Tree
How many children are there? If there is none, then this node represents a leaf node.- Specified by:
getChildCount
in interfaceTree
- Overrides:
getChildCount
in classRuleContext
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getSourceInterval
Description copied from interface:SyntaxTree
Return anInterval
indicating the index in theTokenStream
of the first and last token associated with this subtree. If this node is a leaf, then the interval represents a single token and has interval i..i for token index i.An interval of i..i-1 indicates an empty interval at position i in the input stream, where 0 <= i <= the size of the input token stream. Currently, the code base can only have i=0..n-1 but in concept one could have an empty interval after EOF.
If source interval is unknown, this returns
Interval.INVALID
.As a weird special case, the source interval for rules matched after EOF is unspecified.
- Specified by:
getSourceInterval
in interfaceSyntaxTree
- Overrides:
getSourceInterval
in classRuleContext
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getStart
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. -
getStop
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. -
toInfoString
Used for rule context info debugging during parse-time, not so much for ATN debugging
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