- Direct Known Subclasses:
public abstract class AstNode extends Node implements Comparable<AstNode>Base class for AST node types. The goal of the AST is to represent the physical source code, to make it useful for code-processing tools such as IDEs or pretty-printers. The parser must not rewrite the parse tree when producing this representation.
AstNodehierarchy sits atop the older
Nodeclass, which was designed for code generation. The
Nodeclass is a flexible, weakly-typed class suitable for creating and rewriting code trees, but using it requires you to remember the exact ordering of the child nodes, which are kept in a linked list. The
AstNodehierarchy is a strongly-typed facade with named accessors for children and common properties, but under the hood it's still using a linked list of child nodes. It isn't a very good idea to use the child list directly unless you know exactly what you're doing.
AstNoderecords additional information, including the node's position, length, and parent node. Also, some
AstNodesubclasses record some of their child nodes in instance members, since they are not needed for code generation. In a nutshell, only the code generator should be mixing and matching
All offset fields in all subclasses of AstNode are relative to their parent. For things like paren, bracket and keyword positions, the position is relative to the current node. The node start position is relative to the parent node.
During the actual parsing, node positions are absolute; adding the node to its parent fixes up the offsets to be relative. By the time you see the AST (e.g. using the
Visitorinterface), the offsets are relative.
AstNodeobjects have property lists accessible via the
Node.putProp(int, java.lang.Object)methods. The property lists are integer-keyed with arbitrary
Objectvalues. For the most part the parser generating the AST avoids using properties, preferring fields for elements that are always set. Property lists are intended for user-defined annotations to the tree. The Rhino code generator acts as a client and uses node properties extensively. You are welcome to use the property-list API for anything your client needs.
ATTRIBUTE_FLAG, BOTH, CASEARRAY_PROP, CATCH_SCOPE_PROP, CONTROL_BLOCK_PROP, DECR_FLAG, DESCENDANTS_FLAG, DESTRUCTURING_ARRAY_LENGTH, DESTRUCTURING_NAMES, DESTRUCTURING_PARAMS, DESTRUCTURING_SHORTHAND, DIRECTCALL_PROP, END_DROPS_OFF, END_RETURNS, END_RETURNS_VALUE, END_UNREACHED, END_YIELDS, EXPRESSION_CLOSURE_PROP, FUNCTION_PROP, GENERATOR_END_PROP, INCRDECR_PROP, ISNUMBER_PROP, JSDOC_PROP, LABEL_ID_PROP, LAST_PROP, LEFT, LOCAL_BLOCK_PROP, LOCAL_PROP, MEMBER_TYPE_PROP, NAME_PROP, NON_SPECIALCALL, OBJECT_IDS_PROP, PARENTHESIZED_PROP, POST_FLAG, PROPERTY_FLAG, REGEXP_PROP, RIGHT, SKIP_INDEXES_PROP, SPECIALCALL_EVAL, SPECIALCALL_PROP, SPECIALCALL_WITH, TARGETBLOCK_PROP, VARIABLE_PROP
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description
addChild(AstNode kid)Adds a child or function to the end of the block.
compareTo(AstNode other)Permits AST nodes to be sorted based on start position and length.
debugPrint()Returns a debugging representation of the parse tree starting at this node.
depth()Returns the depth of this node.
getAbsolutePosition()Returns the absolute document position of the node.
getAstRoot()Returns the root of the tree containing this node.
getEnclosingFunction()Returns the innermost enclosing function, or
nullif not in a function.
getEnclosingScope()Returns the innermost enclosing
nullif we're not nested in a scope.
getLength()Returns node length
getLineno()Return the line number recorded for this node.
getParent()Returns the node parent, or
nullif it has none
getPosition()Returns relative position in parent
makeIndent(int indent)Constructs an indentation string.
operatorToString(int op)Returns the string name for this operator.
setBounds(int position, int end)Sets the node start and end positions.
setLength(int length)Sets node length
setParent(AstNode parent)Sets the node parent.
setPosition(int position)Sets relative position in parent
setRelative(int parentPosition)Make this node's position relative to a parent.
shortName()Returns a short, descriptive name for the node, such as "ArrayComprehension".
toSource()Prints the source indented to depth 0.
toSource(int depth)Emits source code for this node.
visit(NodeVisitor visitor)Visits this node and its children in an arbitrary order.
addChildAfter, addChildBefore, addChildrenToBack, addChildrenToFront, addChildToBack, addChildToFront, getChildBefore, getDouble, getExistingIntProp, getFirstChild, getIntProp, getJsDoc, getJsDocNode, getLastChild, getLastSibling, getNext, getProp, getScope, getString, getType, hasChildren, hasConsistentReturnUsage, iterator, labelId, labelId, newNumber, newString, newString, newTarget, putIntProp, putProp, removeChild, removeChildren, removeProp, replaceChild, replaceChildAfter, resetTargets, setDouble, setJsDocNode, setLineno, setScope, setString, setType, toString, toStringTree
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
public AstNode(int pos)Constructs a new AstNode
pos- the start position
public AstNode(int pos, int len)Constructs a new AstNode
pos- the start position
len- the number of characters spanned by the node in the source text
public int getPosition()Returns relative position in parent
public void setPosition(int position)Sets relative position in parent
public int getAbsolutePosition()Returns the absolute document position of the node. Computes it by adding the node's relative position to the relative positions of all its parents.
public int getLength()Returns node length
public void setLength(int length)Sets node length
public void setBounds(int position, int end)Sets the node start and end positions. Computes the length as (
public void setRelative(int parentPosition)Make this node's position relative to a parent. Typically only used by the parser when constructing the node.
parentPosition- the absolute parent position; the current node position is assumed to be absolute and is decremented by parentPosition.
public AstNode getParent()Returns the node parent, or
nullif it has none
public void setParent(AstNode parent)Sets the node parent. This method automatically adjusts the current node's start position to be relative to the new parent.
parent- the new parent. Can be
public void addChild(AstNode kid)Adds a child or function to the end of the block. Sets the parent of the child to this node, and fixes up the start position of the child to be relative to this node. Sets the length of this node to include the new child.
kid- the child
IllegalArgumentException- if kid is
public AstRoot getAstRoot()Returns the root of the tree containing this node.
AstRootat the root of this node's parent chain, or
nullif the topmost parent is not an
public abstract String toSource(int depth)Emits source code for this node. Callee is responsible for calling this function recursively on children, incrementing indent as appropriate.
Note: if the parser was in error-recovery mode, some AST nodes may have
nullchildren that are expected to be non-
nullwhen no errors are present. In this situation, the behavior of the
toSourcemethod is undefined:
toSourceimplementations may assume that the AST node is error-free, since it is intended to be invoked only at runtime after a successful parse.
depth- the current recursion depth, typically beginning at 0 when called on the root node.
public String toSource()Prints the source indented to depth 0.
public String makeIndent(int indent)Constructs an indentation string.
indent- the number of indentation steps
public String shortName()Returns a short, descriptive name for the node, such as "ArrayComprehension".
public static String operatorToString(int op)Returns the string name for this operator.
public abstract void visit(NodeVisitor visitor)Visits this node and its children in an arbitrary order.
It's up to each node subclass to decide the order for processing its children. The subclass also decides (and should document) which child nodes are not passed to the
NodeVisitor. For instance, nodes representing keywords like
inmay not be passed to the visitor object. The visitor can simply query the current node for these children if desired.
Generally speaking, the order will be deterministic; the order is whatever order is decided by each child node. Normally child nodes will try to visit their children in lexical order, but there may be exceptions to this rule.
visitor- the object to call with this node and its children
public static RuntimeException codeBug() throws RuntimeException
public FunctionNode getEnclosingFunction()Returns the innermost enclosing function, or
nullif not in a function. Begins the search with this node's parent.
FunctionNodeenclosing this node, else
public Scope getEnclosingScope()Returns the innermost enclosing
nullif we're not nested in a scope. Begins the search with this node's parent. Note that this is not the same as the defining scope for a
Scopeenclosing this node, else
public int compareTo(AstNode other)Permits AST nodes to be sorted based on start position and length. This makes it easy to sort Comment and Error nodes into a set of other AST nodes: just put them all into a
SortedSet, for instance.
- Specified by:
other- another node
- -1 if this node's start position is less than
other's start position. If tied, -1 if this node's length is less than
other's length. If the lengths are equal, sorts abitrarily on hashcode unless the nodes are the same per
public int depth()Returns the depth of this node. The root is depth 0, its children are depth 1, and so on.
- the node depth in the tree
public int getLineno()Return the line number recorded for this node. If no line number was recorded, searches the parent chain.
public String debugPrint()Returns a debugging representation of the parse tree starting at this node.
- a very verbose indented printout of the tree. The format of each line is: abs-pos name position length [identifier]