RuleContext (ANTLR 4 Runtime (Optimized) 4.11.1 API)

java.lang.Object
- org.antlr.v4.runtime.RuleContext

所有已实现的接口:

ParseTree, RuleNode, SyntaxTree, Tree

直接已知子类:

ParserRuleContext
```
public class RuleContext
extends Object
implements RuleNode
```
A rule context is a record of a single rule invocation. We form a stack of these context objects using the parent pointer. A parent pointer of null indicates that the current context is the bottom of the stack. The ParserRuleContext subclass as a children list so that we can turn this data structure into a tree. The root node always has a null pointer and invokingState of -1. Upon entry to parsing, the first invoked rule function creates a context object (a subclass specialized for that rule such as SContext) and makes it the root of a parse tree, recorded by field Parser._ctx. public final SContext s() throws RecognitionException { SContext _localctx = new SContext(_ctx, getState()); <-- create new node enterRule(_localctx, 0, RULE_s); <-- push it ... exitRule(); <-- pop back to _localctx return _localctx; } A subsequent rule invocation of r from the start rule s pushes a new context object for r whose parent points at s and use invoking state is the state with r emanating as edge label. The invokingState fields from a context object to the root together form a stack of rule indication states where the root (bottom of the stack) has a -1 sentinel value. If we invoke start symbol s then call r1, which calls r2, the would look like this: SContext[-1] <- root node (bottom of the stack) R1Context[p] <- p in rule s called r1 R2Context[q] <- q in rule r1 called r2 So the top of the stack, _ctx, represents a call to the current rule and it holds the return address from another rule that invoke to this rule. To invoke a rule, we must always have a current context. The parent contexts are useful for computing lookahead sets and getting error information. These objects are used during parsing and prediction. For the special case of parsers, we use the subclass ParserRuleContext.

另请参阅:

ParserRuleContext

字段概要

字段
限定符和类型字段和说明

int invokingState
What state invoked the rule associated with this context?

RuleContext parent
What context invoked this rule?

字段
限定符和类型	字段和说明
`int`	`invokingState` What state invoked the rule associated with this context?
`RuleContext`	`parent` What context invoked this rule?

构造器概要

构造器
构造器和说明

RuleContext()

RuleContext(RuleContext parent, int invokingState)

构造器
构造器和说明
`RuleContext()`
`RuleContext(RuleContext parent, int invokingState)`

方法概要

所有方法静态方法实例方法具体方法
限定符和类型	方法和说明
`<T> T`	`accept(ParseTreeVisitor<? extends T> visitor)` The `ParseTreeVisitor` needs a double dispatch method.
`int`	`depth()`
`int`	`getAltNumber()` For rule associated with this parse tree internal node, return the outer alternative number used to match the input.
`ParseTree`	`getChild(int i)` If there are children, get the `i`th value indexed from 0.
`static RuleContext`	`getChildContext(RuleContext parent, int invokingState)`
`int`	`getChildCount()` How many children are there?
`RuleContext`	`getParent()` The parent of this node.
`RuleContext`	`getPayload()` This method returns whatever object represents the data at this node.
`RuleContext`	`getRuleContext()`
`int`	`getRuleIndex()`
`Interval`	`getSourceInterval()` Return an `Interval` indicating the index in the `TokenStream` of the first and last token associated with this subtree.
`String`	`getText()` Return the combined text of all child nodes.
`boolean`	`isEmpty()` A context is empty if there is no invoking state; meaning nobody called current context.
`void`	`setAltNumber(int altNumber)` Set the outer alternative number for this context node.
`void`	`setParent(RuleContext parent)`
`String`	`toString()`
`String`	`toString(List<String> ruleNames)`
`String`	`toString(List<String> ruleNames, RuleContext stop)`
`String`	`toString(Recognizer<?,?> recog)`
`String`	`toString(Recognizer<?,?> recog, RuleContext stop)`
`String`	`toStringTree()` Print out a whole tree, not just a node, in LISP format `(root child1 .. childN)`.
`String`	`toStringTree(List<String> ruleNames)` Print out a whole tree, not just a node, in LISP format (root child1 .. childN).
`String`	`toStringTree(Parser recog)` Print out a whole tree, not just a node, in LISP format (root child1 .. childN).

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- 字段详细资料
  - parent
```
public RuleContext parent
```
    What context invoked this rule?
  - invokingState
```
public int invokingState
```
    What state invoked the rule associated with this context? The "return address" is the followState of invokingState If parent is null, this should be -1 this context object represents the start rule.
- 构造器详细资料
  - RuleContext
```
public RuleContext()
```
  - RuleContext
```
public RuleContext(RuleContext parent,
                   int invokingState)
```
- 方法详细资料
  - getChildContext
```
public static RuleContext getChildContext(RuleContext parent,
                                          int invokingState)
```
  - depth
```
public int depth()
```
  - isEmpty
```
public boolean isEmpty()
```
    A context is empty if there is no invoking state; meaning nobody called current context.
  - getSourceInterval
```
public Interval getSourceInterval()
```
    从接口复制的说明: SyntaxTree
    
    Return an Interval indicating the index in the TokenStream 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.
    
    指定者:
    
    getSourceInterval 在接口中 SyntaxTree
  - getRuleContext
```
public RuleContext getRuleContext()
```
    指定者:
    
    getRuleContext 在接口中 RuleNode
  - getParent
```
public RuleContext getParent()
```
    从接口复制的说明: Tree
    
    The parent of this node. If the return value is null, then this node is the root of the tree.
    
    指定者:
    
    getParent 在接口中 ParseTree
    
    指定者:
    
    getParent 在接口中 RuleNode
    
    指定者:
    
    getParent 在接口中 Tree
  - getPayload
```
public RuleContext getPayload()
```
    从接口复制的说明: Tree
    
    This method returns whatever object represents the data at this node. For example, for parse trees, the payload can be a Token representing a leaf node or a RuleContext object representing a rule invocation. For abstract syntax trees (ASTs), this is a Token object.
    
    指定者:
    
    getPayload 在接口中 Tree
  - getText
```
public String getText()
```
    Return the combined text of all child nodes. This method only considers tokens which have been added to the parse tree.
    Since tokens on hidden channels (e.g. whitespace or comments) are not added to the parse trees, they will not appear in the output of this method.
    
    指定者:
    
    getText 在接口中 ParseTree
  - getRuleIndex
```
public int getRuleIndex()
```
  - getAltNumber
```
public int getAltNumber()
```
    For rule associated with this parse tree internal node, return the outer alternative number used to match the input. Default implementation does not compute nor store this alt num. Create a subclass of ParserRuleContext with backing field and set option contextSuperClass. to set it.
    
    从以下版本开始:
    
    4.5.3
  - setAltNumber
```
public void setAltNumber(int altNumber)
```
    Set the outer alternative number for this context node. Default implementation does nothing to avoid backing field overhead for trees that don't need it. Create a subclass of ParserRuleContext with backing field and set option contextSuperClass.
    
    从以下版本开始:
    
    4.5.3
  - setParent
```
public void setParent(RuleContext parent)
```
    从以下版本开始:
    
    4.7.
  - getChild
```
public ParseTree getChild(int i)
```
    从接口复制的说明: Tree
    
    If there are children, get the ith value indexed from 0.
    
    指定者:
    
    getChild 在接口中 ParseTree
    
    指定者:
    
    getChild 在接口中 Tree
  - getChildCount
```
public int getChildCount()
```
    从接口复制的说明: Tree
    
    How many children are there? If there is none, then this node represents a leaf node.
    
    指定者:
    
    getChildCount 在接口中 Tree
  - accept
```
public <T> T accept(ParseTreeVisitor<? extends T> visitor)
```
    从接口复制的说明: ParseTree
    
    The ParseTreeVisitor needs a double dispatch method.
    
    指定者:
    
    accept 在接口中 ParseTree
  - toStringTree
```
public String toStringTree(@Nullable
                           Parser recog)
```
    Print out a whole tree, not just a node, in LISP format (root child1 .. childN). Print just a node if this is a leaf. We have to know the recognizer so we can get rule names.
    
    指定者:
    
    toStringTree 在接口中 ParseTree
  - toStringTree
```
public String toStringTree(@Nullable
                           List<String> ruleNames)
```
    Print out a whole tree, not just a node, in LISP format (root child1 .. childN). Print just a node if this is a leaf.
  - toStringTree
```
public String toStringTree()
```
    从接口复制的说明: Tree
    
    Print out a whole tree, not just a node, in LISP format (root child1 .. childN). Print just a node if this is a leaf.
    
    指定者:
    
    toStringTree 在接口中 Tree
  - toString
```
public String toString()
```
    覆盖:
    
    toString 在类中 Object
  - toString
```
public final String toString(@Nullable
                             Recognizer<?,?> recog)
```
  - toString
```
public final String toString(@Nullable
                             List<String> ruleNames)
```
  - toString
```
public String toString(@Nullable
                       Recognizer<?,?> recog,
                       @Nullable
                       RuleContext stop)
```
  - toString
```
public String toString(@Nullable
                       List<String> ruleNames,
                       @Nullable
                       RuleContext stop)
```

类 RuleContext

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

parent

invokingState

构造器详细资料

RuleContext

RuleContext

方法详细资料

getChildContext

depth

isEmpty

getSourceInterval

getRuleContext

getParent

getPayload

getText

getRuleIndex

getAltNumber

setAltNumber

setParent

getChild

getChildCount

accept

toStringTree

toStringTree

toStringTree

toString

toString

toString

toString

toString