package persistence.antlr;
/* ANTLR Translator Generator
* Project led by Terence Parr at http://www.jGuru.com
* Software rights: http://www.antlr.org/license.html
*
*/
import persistence.antlr.collections.AST;
import persistence.antlr.collections.impl.ASTArray;
import java.util.Hashtable;
import java.lang.reflect.Constructor;
/** AST Support code shared by TreeParser and Parser.
* We use delegation to share code (and have only one
* bit of code to maintain) rather than subclassing
* or superclassing (forces AST support code to be
* loaded even when you don't want to do AST stuff).
*
* Typically, setASTNodeType is used to specify the
* homogeneous type of node to create, but you can override
* create to make heterogeneous nodes etc...
*/
public class ASTFactory {
/** Name of AST class to create during tree construction.
* Null implies that the create method should create
* a default AST type such as CommonAST. This is for
* homogeneous nodes.
*/
protected String theASTNodeType = null;
protected Class theASTNodeTypeClass = null;
/** How to specify the classname to create for a particular
* token type. Note that ANTLR allows you to say, for example,
*
tokens {
PLUS<AST=PLUSNode>;
...
}
*
* and it tracks everything statically. #[PLUS] will make you
* a PLUSNode w/o use of this table.
*
* For tokens that ANTLR cannot track statically like #[i],
* you can use this table to map PLUS (Integer) -> PLUSNode (Class)
* etc... ANTLR sets the class map from the tokens {...} section
* via the ASTFactory(Hashtable) ctor in persistence.antlr.Parser.
*/
protected Hashtable tokenTypeToASTClassMap = null;
public ASTFactory() {
}
/** Create factory with a specific mapping from token type
* to Java AST node type. Your subclasses of ASTFactory
* can override and reuse the map stuff.
*/
public ASTFactory(Hashtable tokenTypeToClassMap) {
setTokenTypeToASTClassMap(tokenTypeToClassMap);
}
/** Specify an "override" for the Java AST object created for a
* specific token. It is provided as a convenience so
* you can specify node types dynamically. ANTLR sets
* the token type mapping automatically from the tokens{...}
* section, but you can change that mapping with this method.
* ANTLR does it's best to statically determine the node
* type for generating parsers, but it cannot deal with
* dynamic values like #[LT(1)]. In this case, it relies
* on the mapping. Beware differences in the tokens{...}
* section and what you set via this method. Make sure
* they are the same.
*
* Set className to null to remove the mapping.
*
* @since 2.7.2
*/
public void setTokenTypeASTNodeType(int tokenType, String className)
throws IllegalArgumentException
{
if ( tokenTypeToASTClassMap==null ) {
tokenTypeToASTClassMap = new Hashtable();
}
if ( className==null ) {
tokenTypeToASTClassMap.remove(new Integer(tokenType));
return;
}
Class c = null;
try {
c = Class.forName(className);
tokenTypeToASTClassMap.put(new Integer(tokenType), c);
}
catch (Exception e) {
throw new IllegalArgumentException("Invalid class, "+className);
}
}
/** For a given token type, what is the AST node object type to create
* for it?
* @since 2.7.2
*/
public Class getASTNodeType(int tokenType) {
// try node specific class
if ( tokenTypeToASTClassMap!=null ) {
Class c = (Class)tokenTypeToASTClassMap.get(new Integer(tokenType));
if ( c!=null ) {
return c;
}
}
// try a global specified class
if (theASTNodeTypeClass != null) {
return theASTNodeTypeClass;
}
// default to the common type
return CommonAST.class;
}
/** Add a child to the current AST */
public void addASTChild(ASTPair currentAST, AST child) {
if (child != null) {
if (currentAST.root == null) {
// Make new child the current root
currentAST.root = child;
}
else {
if (currentAST.child == null) {
// Add new child to current root
currentAST.root.setFirstChild(child);
}
else {
currentAST.child.setNextSibling(child);
}
}
// Make new child the current child
currentAST.child = child;
currentAST.advanceChildToEnd();
}
}
/** Create a new empty AST node; if the user did not specify
* an AST node type, then create a default one: CommonAST.
*/
public AST create() {
return create(Token.INVALID_TYPE);
}
public AST create(int type) {
Class c = getASTNodeType(type);
AST t = create(c);
if ( t!=null ) {
t.initialize(type, "");
}
return t;
}
public AST create(int type, String txt) {
AST t = create(type);
if ( t!=null ) {
t.initialize(type, txt);
}
return t;
}
/** Create an AST node with the token type and text passed in, but
* with a specific Java object type. Typically called when you
* say @[PLUS,"+",PLUSNode] in an antlr action.
* @since 2.7.2
*/
public AST create(int type, String txt, String className) {
AST t = create(className);
if ( t!=null ) {
t.initialize(type, txt);
}
return t;
}
/** Create a new empty AST node; if the user did not specify
* an AST node type, then create a default one: CommonAST.
*/
public AST create(AST tr) {
if (tr == null) return null; // create(null) == null
AST t = create(tr.getType());
if ( t!=null ) {
t.initialize(tr);
}
return t;
}
public AST create(Token tok) {
AST t = create(tok.getType());
if ( t!=null ) {
t.initialize(tok);
}
return t;
}
/** ANTLR generates reference to this when you reference a token
* that has a specified heterogeneous AST node type. This is
* also a special case node creation routine for backward
* compatibility. Before, ANTLR generated "new T(tokenObject)"
* and so I must call the appropriate constructor not T().
*
* @since 2.7.2
*/
public AST create(Token tok, String className) {
AST t = createUsingCtor(tok,className);
return t;
}
/**
* @since 2.7.2
*/
public AST create(String className) {
Class c = null;
try {
c = Class.forName(className);
}
catch (Exception e) {
throw new IllegalArgumentException("Invalid class, "+className);
}
return create(c);
}
/**
* @since 2.7.2
*/
protected AST createUsingCtor(Token token, String className) {
Class c = null;
AST t = null;
try {
c = Class.forName(className);
Class[] tokenArgType = new Class[] { persistence.antlr.Token.class };
try {
Constructor ctor = c.getConstructor(tokenArgType);
t = (AST)ctor.newInstance(new Object[]{token}); // make a new one
}
catch (NoSuchMethodException e){
// just do the regular thing if you can't find the ctor
// Your AST must have default ctor to use this.
t = create(c);
if ( t!=null ) {
t.initialize(token);
}
}
}
catch (Exception e) {
throw new IllegalArgumentException("Invalid class or can't make instance, "+className);
}
return t;
}
/**
* @since 2.7.2
*/
protected AST create(Class c) {
AST t = null;
try {
t = (AST)c.newInstance(); // make a new one
}
catch (Exception e) {
error("Can't create AST Node " + c.getName());
return null;
}
return t;
}
/** Copy a single node with same Java AST objec type.
* Ignore the tokenType->Class mapping since you know
* the type of the node, t.getClass(), and doing a dup.
*
* clone() is not used because we want all AST creation
* to go thru the factory so creation can be
* tracked. Returns null if t is null.
*/
public AST dup(AST t) {
if ( t==null ) {
return null;
}
AST dup_t = create(t.getClass());
dup_t.initialize(t);
return dup_t;
}
/** Duplicate tree including siblings of root. */
public AST dupList(AST t) {
AST result = dupTree(t); // if t == null, then result==null
AST nt = result;
while (t != null) { // for each sibling of the root
t = t.getNextSibling();
nt.setNextSibling(dupTree(t)); // dup each subtree, building new tree
nt = nt.getNextSibling();
}
return result;
}
/**Duplicate a tree, assuming this is a root node of a tree--
* duplicate that node and what's below; ignore siblings of root node.
*/
public AST dupTree(AST t) {
AST result = dup(t); // make copy of root
// copy all children of root.
if (t != null) {
result.setFirstChild(dupList(t.getFirstChild()));
}
return result;
}
/** Make a tree from a list of nodes. The first element in the
* array is the root. If the root is null, then the tree is
* a simple list not a tree. Handles null children nodes correctly.
* For example, build(a, b, null, c) yields tree (a b c). build(null,a,b)
* yields tree (nil a b).
*/
public AST make(AST[] nodes) {
if (nodes == null || nodes.length == 0) return null;
AST root = nodes[0];
AST tail = null;
if (root != null) {
root.setFirstChild(null); // don't leave any old pointers set
}
// link in children;
for (int i = 1; i < nodes.length; i++) {
if (nodes[i] == null) continue; // ignore null nodes
if (root == null) {
// Set the root and set it up for a flat list
root = tail = nodes[i];
}
else if (tail == null) {
root.setFirstChild(nodes[i]);
tail = root.getFirstChild();
}
else {
tail.setNextSibling(nodes[i]);
tail = tail.getNextSibling();
}
// Chase tail to last sibling
while (tail.getNextSibling() != null) {
tail = tail.getNextSibling();
}
}
return root;
}
/** Make a tree from a list of nodes, where the nodes are contained
* in an ASTArray object
*/
public AST make(ASTArray nodes) {
return make(nodes.array);
}
/** Make an AST the root of current AST */
public void makeASTRoot(ASTPair currentAST, AST root) {
if (root != null) {
// Add the current root as a child of new root
root.addChild(currentAST.root);
// The new current child is the last sibling of the old root
currentAST.child = currentAST.root;
currentAST.advanceChildToEnd();
// Set the new root
currentAST.root = root;
}
}
public void setASTNodeClass(String t) {
theASTNodeType = t;
try {
theASTNodeTypeClass = Class.forName(t); // get class def
}
catch (Exception e) {
// either class not found,
// class is interface/abstract, or
// class or initializer is not accessible.
error("Can't find/access AST Node type" + t);
}
}
/** Specify the type of node to create during tree building.
* @deprecated since 2.7.1
*/
public void setASTNodeType(String t) {
setASTNodeClass(t);
}
public Hashtable getTokenTypeToASTClassMap() {
return tokenTypeToASTClassMap;
}
public void setTokenTypeToASTClassMap(Hashtable tokenTypeToClassMap) {
this.tokenTypeToASTClassMap = tokenTypeToClassMap;
}
/** To change where error messages go, can subclass/override this method
* and then setASTFactory in Parser and TreeParser. This method removes
* a prior dependency on class persistence.antlr.Tool.
*/
public void error(String e) {
System.err.println(e);
}
}
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