org.antlr.runtime.tree

Class TreeWizard

java.lang.Object

org.antlr.runtime.tree.TreeWizard

public class TreeWizard
extends Object

Build and navigate trees with this object. Must know about the names of tokens so you have to pass in a map or array of token names (from which this class can build the map). I.e., Token DECL means nothing unless the class can translate it to a token type. In order to create nodes and navigate, this class needs a TreeAdaptor. This class can build a token type → node index for repeated use or for iterating over the various nodes with a particular type. This class works in conjunction with the TreeAdaptor rather than moving all this functionality into the adaptor. An adaptor helps build and navigate trees using methods. This class helps you do it with string patterns like "(A B C)". You can create a tree from that pattern or match subtrees against it.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	TreeWizard.ContextVisitor
static class	TreeWizard.TreePattern When using %label:TOKENNAME in a tree for parse(), we must track the label.
static class	TreeWizard.TreePatternTreeAdaptor This adaptor creates TreePattern objects for use during scan()
static class	TreeWizard.Visitor
static class	TreeWizard.WildcardTreePattern

Field Summary

Fields

Modifier and Type	Field and Description
protected TreeAdaptor	adaptor
protected Map<String,Integer>	tokenNameToTypeMap

Constructor Summary

Constructors

Constructor and Description
TreeWizard(String[] tokenNames)
TreeWizard(TreeAdaptor adaptor) During fillBuffer(), we can make a reverse index from a set of token types of interest to the list of indexes into the node stream.
TreeWizard(TreeAdaptor adaptor, Map<String,Integer> tokenNameToTypeMap)
TreeWizard(TreeAdaptor adaptor, String[] tokenNames)

Method Summary

Methods

Modifier and Type	Method and Description
protected static boolean	_equals(Object t1, Object t2, TreeAdaptor adaptor)
protected void	_index(Object t, Map<Integer,List<Object>> m) Do the work for index
protected boolean	_parse(Object t1, TreeWizard.TreePattern tpattern, Map<String,Object> labels) Do the work for parse.
protected void	_visit(Object t, Object parent, int childIndex, int ttype, TreeWizard.ContextVisitor visitor) Do the recursive work for visit
Map<String,Integer>	computeTokenTypes(String[] tokenNames) Compute a Map<String, Integer> that is an inverted index of tokenNames (which maps int token types to names).
Object	create(String pattern) Create a tree or node from the indicated tree pattern that closely follows ANTLR tree grammar tree element syntax: (root child1 ...
boolean	equals(Object t1, Object t2) Compare type, structure, and text of two trees, assuming adaptor in this instance of a TreeWizard.
static boolean	equals(Object t1, Object t2, TreeAdaptor adaptor) Compare t1 and t2; return true if token types/text, structure match exactly.
List<? extends Object>	find(Object t, int ttype) Return a List of tree nodes with token type ttype
List<? extends Object>	find(Object t, String pattern) Return a List of subtrees matching pattern.
Object	findFirst(Object t, int ttype)
Object	findFirst(Object t, String pattern)
int	getTokenType(String tokenName) Using the map of token names to token types, return the type.
Map<Integer,List<Object>>	index(Object t) Walk the entire tree and make a node name to nodes mapping.
boolean	parse(Object t, String pattern)
boolean	parse(Object t, String pattern, Map<String,Object> labels) Given a pattern like (ASSIGN %lhs:ID %rhs:.) with optional labels on the various nodes and '.' (dot) as the node/subtree wildcard, return true if the pattern matches and fill the labels Map with the labels pointing at the appropriate nodes.
void	visit(Object t, int ttype, TreeWizard.ContextVisitor visitor) Visit every ttype node in t, invoking the visitor.
void	visit(Object t, String pattern, TreeWizard.ContextVisitor visitor) For all subtrees that match the pattern, execute the visit action.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

adaptor

protected TreeAdaptor adaptor

tokenNameToTypeMap

protected Map<String,Integer> tokenNameToTypeMap

Constructor Detail

TreeWizard

public TreeWizard(TreeAdaptor adaptor)

During fillBuffer(), we can make a reverse index from a set of token types of interest to the list of indexes into the node stream. This lets us convert a node pointer to a stream index semi-efficiently for a list of interesting nodes such as function definition nodes (you'll want to seek to their bodies for an interpreter). Also useful for doing dynamic searches; i.e., go find me all PLUS nodes. protected Map tokenTypeToStreamIndexesMap; /** If tokenTypesToReverseIndex set to INDEX_ALL then indexing occurs for all token types. public static final Set INDEX_ALL = new HashSet(); /** A set of token types user would like to index for faster lookup. If this is INDEX_ALL, then all token types are tracked. If null, then none are indexed. protected Set tokenTypesToReverseIndex = null;

TreeWizard

public TreeWizard(TreeAdaptor adaptor,
          Map<String,Integer> tokenNameToTypeMap)

TreeWizard

public TreeWizard(TreeAdaptor adaptor,
          String[] tokenNames)

TreeWizard

public TreeWizard(String[] tokenNames)

Method Detail

computeTokenTypes

public Map<String,Integer> computeTokenTypes(String[] tokenNames)

Compute a Map<String, Integer> that is an inverted index of tokenNames (which maps int token types to names).

getTokenType

public int getTokenType(String tokenName)

Using the map of token names to token types, return the type.

index

public Map<Integer,List<Object>> index(Object t)

Walk the entire tree and make a node name to nodes mapping. For now, use recursion but later nonrecursive version may be more efficient. Returns Map<Integer, List> where the List is of your AST node type. The Integer is the token type of the node. TODO: save this index so that find and visit are faster

_index

protected void _index(Object t,
          Map<Integer,List<Object>> m)

Do the work for index

find

public List<? extends Object> find(Object t,
                          int ttype)

Return a List of tree nodes with token type ttype

find

public List<? extends Object> find(Object t,
                          String pattern)

Return a List of subtrees matching pattern.

findFirst

public Object findFirst(Object t,
               int ttype)

findFirst

public Object findFirst(Object t,
               String pattern)

visit

public void visit(Object t,
         int ttype,
         TreeWizard.ContextVisitor visitor)

Visit every ttype node in t, invoking the visitor. This is a quicker version of the general visit(t, pattern) method. The labels arg of the visitor action method is never set (it's null) since using a token type rather than a pattern doesn't let us set a label.

_visit

protected void _visit(Object t,
          Object parent,
          int childIndex,
          int ttype,
          TreeWizard.ContextVisitor visitor)

Do the recursive work for visit

visit

public void visit(Object t,
         String pattern,
         TreeWizard.ContextVisitor visitor)

For all subtrees that match the pattern, execute the visit action. The implementation uses the root node of the pattern in combination with visit(t, ttype, visitor) so nil-rooted patterns are not allowed. Patterns with wildcard roots are also not allowed.

parse

public boolean parse(Object t,
            String pattern,
            Map<String,Object> labels)

Given a pattern like (ASSIGN %lhs:ID %rhs:.) with optional labels on the various nodes and '.' (dot) as the node/subtree wildcard, return true if the pattern matches and fill the labels Map with the labels pointing at the appropriate nodes. Return false if the pattern is malformed or the tree does not match. If a node specifies a text arg in pattern, then that must match for that node in t. TODO: what's a better way to indicate bad pattern? Exceptions are a hassle

parse

public boolean parse(Object t,
            String pattern)

_parse

protected boolean _parse(Object t1,
             TreeWizard.TreePattern tpattern,
             Map<String,Object> labels)

Do the work for parse. Check to see if the t2 pattern fits the structure and token types in t1. Check text if the pattern has text arguments on nodes. Fill labels map with pointers to nodes in tree matched against nodes in pattern with labels.

create

public Object create(String pattern)

Create a tree or node from the indicated tree pattern that closely follows ANTLR tree grammar tree element syntax: (root child1 ... child2). You can also just pass in a node: ID Any node can have a text argument: ID[foo] (notice there are no quotes around foo--it's clear it's a string). nil is a special name meaning "give me a nil node". Useful for making lists: (nil A B C) is a list of A B C.

equals

public static boolean equals(Object t1,
             Object t2,
             TreeAdaptor adaptor)

Compare t1 and t2; return true if token types/text, structure match exactly. The trees are examined in their entirety so that (A B) does not match (A B C) nor (A (B C)). // TODO: allow them to pass in a comparator TODO: have a version that is nonstatic so it can use instance adaptor I cannot rely on the tree node's equals() implementation as I make no constraints at all on the node types nor interface etc...

equals

public boolean equals(Object t1,
             Object t2)

Compare type, structure, and text of two trees, assuming adaptor in this instance of a TreeWizard.

_equals

protected static boolean _equals(Object t1,
              Object t2,
              TreeAdaptor adaptor)