src/antlr/ASTFactory.cpp

/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/license.html
 *
 * $Id: ASTFactory.cpp,v 1.1 2005-12-02 15:38:02 tim Exp $
 */

#include "antlr/CommonAST.hpp"
#include "antlr/ANTLRException.hpp"
#include "antlr/IOException.hpp"
#include "antlr/ASTFactory.hpp"
#include "antlr/ANTLRUtil.hpp"

#include <iostream>
#include <istream>

using namespace std;

#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
namespace antlr {
#endif

/** 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).
 *
 * This class collects all factories of AST types used inside the code.
 * New AST node types are registered with the registerFactory method.
 * On creation of an ASTFactory object a default AST node factory may be
 * specified.
 *
 * When registering types gaps between different types are filled with entries
 * for the default factory.
 */

/// Initialize factory
ASTFactory::ASTFactory()
: default_factory_descriptor(ANTLR_USE_NAMESPACE(std)make_pair(CommonAST::TYPE_NAME,&CommonAST::factory))
{
        nodeFactories.resize( Token::MIN_USER_TYPE, &default_factory_descriptor );
}

/** Initialize factory with a non default node type.
 * factory_node_name should be the name of the AST node type the factory
 * generates. (should exist during the existance of this ASTFactory instance)
 */
ASTFactory::ASTFactory( const char* factory_node_name, factory_type fact )
: default_factory_descriptor(ANTLR_USE_NAMESPACE(std)make_pair(factory_node_name, fact))
{
        nodeFactories.resize( Token::MIN_USER_TYPE, &default_factory_descriptor );
}

/// Delete ASTFactory
ASTFactory::~ASTFactory()
{
        factory_descriptor_list::iterator i = nodeFactories.begin();

        while( i != nodeFactories.end() )
        {
                if( *i != &default_factory_descriptor )
                        delete *i;
                i++;
        }
}

/// Register a factory for a given AST type
void ASTFactory::registerFactory( int type, const char* ast_name, factory_type factory )
{
        // check validity of arguments...
        if( type < Token::MIN_USER_TYPE )
                throw ANTLRException("Internal parser error invalid type passed to RegisterFactory");
        if( factory == 0 )
                throw ANTLRException("Internal parser error 0 factory passed to RegisterFactory");

        // resize up to and including 'type' and initalize any gaps to default
        // factory.
        if( nodeFactories.size() < (static_cast<unsigned int>(type)+1) )
                nodeFactories.resize( type+1, &default_factory_descriptor );

        // And add new thing..
        nodeFactories[type] = new ANTLR_USE_NAMESPACE(std)pair<const char*, factory_type>( ast_name, factory );
}

void ASTFactory::setMaxNodeType( int type )
{
        if( nodeFactories.size() < (static_cast<unsigned int>(type)+1) )
                nodeFactories.resize( type+1, &default_factory_descriptor );
}

/** Create a new empty AST node; if the user did not specify
 *  an AST node type, then create a default one: CommonAST.
 */
RefAST ASTFactory::create()
{
        RefAST node = nodeFactories[0]->second();
        node->setType(Token::INVALID_TYPE);
        return node;
}

RefAST ASTFactory::create(int type)
{
        RefAST t = nodeFactories[type]->second();
        t->initialize(type,"");
        return t;
}

RefAST ASTFactory::create(int type, const ANTLR_USE_NAMESPACE(std)string& txt)
{
        RefAST t = nodeFactories[type]->second();
        t->initialize(type,txt);
        return t;
}

#ifdef ANTLR_SUPPORT_XML
RefAST ASTFactory::create(const ANTLR_USE_NAMESPACE(std)string& type_name, ANTLR_USE_NAMESPACE(std)istream& infile )
{
        factory_descriptor_list::iterator fact = nodeFactories.begin();

        while( fact != nodeFactories.end() )
        {
                if( type_name == (*fact)->first )
                {
                        RefAST t = (*fact)->second();
                        t->initialize(infile);
                        return t;
                }
                fact++;
        }

        string error = "ASTFactory::create: Unknown AST type '" + type_name + "'";
        throw ANTLRException(error);
}
#endif

/** Create a new empty AST node; if the user did not specify
 *  an AST node type, then create a default one: CommonAST.
 */
RefAST ASTFactory::create(RefAST tr)
{
        if (!tr)
                return nullAST;

//      cout << "create(tr)" << endl;

        RefAST t = nodeFactories[tr->getType()]->second();
        t->initialize(tr);
        return t;
}

RefAST ASTFactory::create(RefToken tok)
{
//      cout << "create( tok="<< tok->getType() << ", " << tok->getText() << ")" << nodeFactories.size() << endl;
        RefAST t = nodeFactories[tok->getType()]->second();
        t->initialize(tok);
        return t;
}

/** Add a child to the current AST */
void ASTFactory::addASTChild(ASTPair& currentAST, RefAST child)
{
        if (child)
        {
                if (!currentAST.root)
                {
                        // Make new child the current root
                        currentAST.root = child;
                }
                else
                {
                        if (!currentAST.child)
                        {
                                // 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();
        }
}

/** Deep copy a single node. This function the new clone() methods in the AST
 * interface. Returns nullAST if t is null.
 */
RefAST ASTFactory::dup(RefAST t)
{
        if( t )
                return t->clone();
        else
                return RefAST(nullASTptr);
}

/** Duplicate tree including siblings of root. */
RefAST ASTFactory::dupList(RefAST t)
{
        RefAST result = dupTree(t);         // if t == null, then result==null
        RefAST nt = result;

        while( t )
        {                                                                                               // 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.
 */
RefAST ASTFactory::dupTree(RefAST t)
{
        RefAST result = dup(t);         // make copy of root
        // copy all children of root.
        if( t )
                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, make(a, b, null, c) yields tree (a b c).  make(null,a,b)
 * yields tree (nil a b).
 */
RefAST ASTFactory::make(ANTLR_USE_NAMESPACE(std)vector<RefAST>& nodes)
{
        if ( nodes.size() == 0 )
                return RefAST(nullASTptr);

        RefAST root = nodes[0];
        RefAST tail = RefAST(nullASTptr);

        if( root )
                root->setFirstChild(RefAST(nullASTptr));        // don't leave any old pointers set

        // link in children;
        for( unsigned int i = 1; i < nodes.size(); i++ )
        {
                if ( nodes[i] == 0 )            // ignore null nodes
                        continue;

                if ( root == 0 )                        // Set the root and set it up for a flat list
                        root = tail = nodes[i];
                else if ( tail == 0 )
                {
                        root->setFirstChild(nodes[i]);
                        tail = root->getFirstChild();
                }
                else
                {
                        tail->setNextSibling(nodes[i]);
                        tail = tail->getNextSibling();
                }

                if( tail )      // RK: I cannot fathom why this missing check didn't bite anyone else...
                {
                        // Chase tail to last sibling
                        while (tail->getNextSibling())
                                tail = tail->getNextSibling();
                }
        }

        return root;
}

/** Make a tree from a list of nodes, where the nodes are contained
 * in an ASTArray object
 */
RefAST ASTFactory::make(ASTArray* nodes)
{
        RefAST ret = make(nodes->array);
        delete nodes;
        return ret;
}

/// Make an AST the root of current AST
void ASTFactory::makeASTRoot( ASTPair& currentAST, RefAST root )
{
        if (root)
        {
                // 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;
        }
}

void ASTFactory::setASTNodeFactory( const char* factory_node_name,
                                                                                           factory_type factory )
{
        default_factory_descriptor.first = factory_node_name;
        default_factory_descriptor.second = factory;
}

#ifdef ANTLR_SUPPORT_XML
bool ASTFactory::checkCloseTag( ANTLR_USE_NAMESPACE(std)istream& in )
{
        char ch;

        if( in.get(ch) )
        {
                if( ch == '<' )
                {
                        char ch2;
                        if( in.get(ch2) )
                        {
                                if( ch2 == '/' )
                                {
                                        in.putback(ch2);
                                        in.putback(ch);
                                        return true;
                                }
                                in.putback(ch2);
                                in.putback(ch);
                                return false;
                        }
                }
                in.putback(ch);
                return false;
        }
        return false;
}

void ASTFactory::loadChildren( ANTLR_USE_NAMESPACE(std)istream& infile,
                                                                                 RefAST current )
{
        char ch;

        for(;;)                 // for all children of this node....
        {
                eatwhite(infile);

                infile.get(ch); // '<'
                if( ch != '<' )
                {
                        string error = "Invalid XML file... no '<' found (";
                        error += ch + ")";
                        throw IOException(error);
                }

                infile.get(ch);         // / or text....

                if( ch == '/' )         // check for close tag...
                {
                        string temp;

                        // read until '>' and see if it matches the open tag... if not trouble
                        temp = read_identifier( infile );

                        if( strcmp(temp.c_str(), current->typeName() ) != 0 )
                        {
                                string error = "Invalid XML file... close tag does not match start tag: ";
                                error += current->typeName();
                                error += " closed by " + temp;
                                throw IOException(error);
                        }

                        infile.get(ch); // must be a '>'

                        if( ch != '>' )
                        {
                                string error = "Invalid XML file... no '>' found (";
                                error += ch + ")";
                                throw IOException(error);
                        }
                        // close tag => exit loop
                        break;
                }

                // put our 'look ahead' back where it came from
                infile.putback(ch);
                infile.putback('<');

                // and recurse into the tree...
                RefAST child = LoadAST(infile);

                current->addChild( child );
        }
}

void ASTFactory::loadSiblings(ANTLR_USE_NAMESPACE(std)istream& infile,
                                                                                RefAST current )
{
        for(;;)
        {
                eatwhite(infile);

                if( infile.eof() )
                        break;

                if( checkCloseTag(infile) )
                        break;

                RefAST sibling = LoadAST(infile);
                current->setNextSibling(sibling);
        }
}

RefAST ASTFactory::LoadAST( ANTLR_USE_NAMESPACE(std)istream& infile )
{
        RefAST current = nullAST;
        char ch;

        eatwhite(infile);

        if( !infile.get(ch) )
                return nullAST;

        if( ch != '<' )
        {
                string error = "Invalid XML file... no '<' found (";
                error += ch + ")";
                throw IOException(error);
        }

        string ast_type = read_identifier(infile);

        // create the ast of type 'ast_type'
        current = create( ast_type, infile );
        if( current == nullAST )
        {
                string error = "Unsuported AST type: " + ast_type;
                throw IOException(error);
        }

        eatwhite(infile);

        infile.get(ch);

        // now if we have a '/' here it's a single node. If it's a '>' we get
        // a tree with children

        if( ch == '/' )
        {
                infile.get(ch);         // get the closing '>'
                if( ch != '>' )
                {
                        string error = "Invalid XML file... no '>' found after '/' (";
                        error += ch + ")";
                        throw IOException(error);
                }

                // get the rest on this level
                loadSiblings( infile, current );

                return current;
        }

        // and finaly see if we got the close tag...
        if( ch != '>' )
        {
                string error = "Invalid XML file... no '>' found (";
                error += ch + ")";
                throw IOException(error);
        }

        // handle the ones below this level..
        loadChildren( infile, current );

        // load the rest on this level...
        loadSiblings( infile, current );

        return current;
}
#endif // ANTLR_SUPPORT_XML

#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
}
#endif

/* Heterogeneous AST/XML-I/O ramblings...
 *
 * So there is some heterogeneous AST support....
 * basically in the code generators a new custom ast is generated without
 * going throug the factory. It also expects the RefXAST to be defined.
 *
 * Is it maybe better to register all AST types with the ASTFactory class
 * together with the respective factory methods.
 *
 * More and more I get the impression that hetero ast was a kindoff hack
 * on top of ANTLR's normal AST system.
 *
 * The heteroast stuff will generate trouble for all astFactory.create( ... )
 * invocations. Most of this is handled via getASTCreateString methods in the
 * codegenerator. At the moment getASTCreateString(GrammarAtom, String) has
 * slightly to little info to do it's job (ok the hack that is in now
 * works, but it's an ugly hack)
 *
 * An extra caveat is the 'nice' action.g thing. Which also judiciously calls
 * getASTCreateString methods because it handles the #( ... ) syntax.
 * And converts that to ASTFactory calls.
 *
 *
 */
Revision:	770
Committed:	Fri Dec 2 15:38:03 2005 UTC (19 years, 10 months ago) by tim
File size:	12334 byte(s)
Log Message:	End of the Link --> List Return of the Oject-Oriented replace yacc/lex parser with antlr parser
#	Content
1	/* ANTLR Translator Generator
2	* Project led by Terence Parr at http://www.jGuru.com
3	* Software rights: http://www.antlr.org/license.html
4	*
5	* $Id: ASTFactory.cpp,v 1.1 2005-12-02 15:38:02 tim Exp $
6	*/
7
8	#include "antlr/CommonAST.hpp"
9	#include "antlr/ANTLRException.hpp"
10	#include "antlr/IOException.hpp"
11	#include "antlr/ASTFactory.hpp"
12	#include "antlr/ANTLRUtil.hpp"
13
14	#include <iostream>
15	#include <istream>
16
17	using namespace std;
18
19	#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
20	namespace antlr {
21	#endif
22
23	/** AST Support code shared by TreeParser and Parser.
24	* We use delegation to share code (and have only one
25	* bit of code to maintain) rather than subclassing
26	* or superclassing (forces AST support code to be
27	* loaded even when you don't want to do AST stuff).
28	*
29	* This class collects all factories of AST types used inside the code.
30	* New AST node types are registered with the registerFactory method.
31	* On creation of an ASTFactory object a default AST node factory may be
32	* specified.
33	*
34	* When registering types gaps between different types are filled with entries
35	* for the default factory.
36	*/
37
38	/// Initialize factory
39	ASTFactory::ASTFactory()
40	: default_factory_descriptor(ANTLR_USE_NAMESPACE(std)make_pair(CommonAST::TYPE_NAME,&CommonAST::factory))
41	{
42	nodeFactories.resize( Token::MIN_USER_TYPE, &default_factory_descriptor );
43	}
44
45	/** Initialize factory with a non default node type.
46	* factory_node_name should be the name of the AST node type the factory
47	* generates. (should exist during the existance of this ASTFactory instance)
48	*/
49	ASTFactory::ASTFactory( const char* factory_node_name, factory_type fact )
50	: default_factory_descriptor(ANTLR_USE_NAMESPACE(std)make_pair(factory_node_name, fact))
51	{
52	nodeFactories.resize( Token::MIN_USER_TYPE, &default_factory_descriptor );
53	}
54
55	/// Delete ASTFactory
56	ASTFactory::~ASTFactory()
57	{
58	factory_descriptor_list::iterator i = nodeFactories.begin();
59
60	while( i != nodeFactories.end() )
61	{
62	if( *i != &default_factory_descriptor )
63	delete *i;
64	i++;
65	}
66	}
67
68	/// Register a factory for a given AST type
69	void ASTFactory::registerFactory( int type, const char* ast_name, factory_type factory )
70	{
71	// check validity of arguments...
72	if( type < Token::MIN_USER_TYPE )
73	throw ANTLRException("Internal parser error invalid type passed to RegisterFactory");
74	if( factory == 0 )
75	throw ANTLRException("Internal parser error 0 factory passed to RegisterFactory");
76
77	// resize up to and including 'type' and initalize any gaps to default
78	// factory.
79	if( nodeFactories.size() < (static_cast<unsigned int>(type)+1) )
80	nodeFactories.resize( type+1, &default_factory_descriptor );
81
82	// And add new thing..
83	nodeFactories[type] = new ANTLR_USE_NAMESPACE(std)pair<const char*, factory_type>( ast_name, factory );
84	}
85
86	void ASTFactory::setMaxNodeType( int type )
87	{
88	if( nodeFactories.size() < (static_cast<unsigned int>(type)+1) )
89	nodeFactories.resize( type+1, &default_factory_descriptor );
90	}
91
92	/** Create a new empty AST node; if the user did not specify
93	* an AST node type, then create a default one: CommonAST.
94	*/
95	RefAST ASTFactory::create()
96	{
97	RefAST node = nodeFactories[0]->second();
98	node->setType(Token::INVALID_TYPE);
99	return node;
100	}
101
102	RefAST ASTFactory::create(int type)
103	{
104	RefAST t = nodeFactories[type]->second();
105	t->initialize(type,"");
106	return t;
107	}
108
109	RefAST ASTFactory::create(int type, const ANTLR_USE_NAMESPACE(std)string& txt)
110	{
111	RefAST t = nodeFactories[type]->second();
112	t->initialize(type,txt);
113	return t;
114	}
115
116	#ifdef ANTLR_SUPPORT_XML
117	RefAST ASTFactory::create(const ANTLR_USE_NAMESPACE(std)string& type_name, ANTLR_USE_NAMESPACE(std)istream& infile )
118	{
119	factory_descriptor_list::iterator fact = nodeFactories.begin();
120
121	while( fact != nodeFactories.end() )
122	{
123	if( type_name == (*fact)->first )
124	{
125	RefAST t = (*fact)->second();
126	t->initialize(infile);
127	return t;
128	}
129	fact++;
130	}
131
132	string error = "ASTFactory::create: Unknown AST type '" + type_name + "'";
133	throw ANTLRException(error);
134	}
135	#endif
136
137	/** Create a new empty AST node; if the user did not specify
138	* an AST node type, then create a default one: CommonAST.
139	*/
140	RefAST ASTFactory::create(RefAST tr)
141	{
142	if (!tr)
143	return nullAST;
144
145	// cout << "create(tr)" << endl;
146
147	RefAST t = nodeFactories[tr->getType()]->second();
148	t->initialize(tr);
149	return t;
150	}
151
152	RefAST ASTFactory::create(RefToken tok)
153	{
154	// cout << "create( tok="<< tok->getType() << ", " << tok->getText() << ")" << nodeFactories.size() << endl;
155	RefAST t = nodeFactories[tok->getType()]->second();
156	t->initialize(tok);
157	return t;
158	}
159
160	/** Add a child to the current AST */
161	void ASTFactory::addASTChild(ASTPair& currentAST, RefAST child)
162	{
163	if (child)
164	{
165	if (!currentAST.root)
166	{
167	// Make new child the current root
168	currentAST.root = child;
169	}
170	else
171	{
172	if (!currentAST.child)
173	{
174	// Add new child to current root
175	currentAST.root->setFirstChild(child);
176	}
177	else
178	{
179	currentAST.child->setNextSibling(child);
180	}
181	}
182	// Make new child the current child
183	currentAST.child = child;
184	currentAST.advanceChildToEnd();
185	}
186	}
187
188	/** Deep copy a single node. This function the new clone() methods in the AST
189	* interface. Returns nullAST if t is null.
190	*/
191	RefAST ASTFactory::dup(RefAST t)
192	{
193	if( t )
194	return t->clone();
195	else
196	return RefAST(nullASTptr);
197	}
198
199	/** Duplicate tree including siblings of root. */
200	RefAST ASTFactory::dupList(RefAST t)
201	{
202	RefAST result = dupTree(t); // if t == null, then result==null
203	RefAST nt = result;
204
205	while( t )
206	{ // for each sibling of the root
207	t = t->getNextSibling();
208	nt->setNextSibling(dupTree(t)); // dup each subtree, building new tree
209	nt = nt->getNextSibling();
210	}
211	return result;
212	}
213
214	/** Duplicate a tree, assuming this is a root node of a tree
215	* duplicate that node and what's below; ignore siblings of root node.
216	*/
217	RefAST ASTFactory::dupTree(RefAST t)
218	{
219	RefAST result = dup(t); // make copy of root
220	// copy all children of root.
221	if( t )
222	result->setFirstChild( dupList(t->getFirstChild()) );
223	return result;
224	}
225
226	/** Make a tree from a list of nodes. The first element in the
227	* array is the root. If the root is null, then the tree is
228	* a simple list not a tree. Handles null children nodes correctly.
229	* For example, make(a, b, null, c) yields tree (a b c). make(null,a,b)
230	* yields tree (nil a b).
231	*/
232	RefAST ASTFactory::make(ANTLR_USE_NAMESPACE(std)vector<RefAST>& nodes)
233	{
234	if ( nodes.size() == 0 )
235	return RefAST(nullASTptr);
236
237	RefAST root = nodes[0];
238	RefAST tail = RefAST(nullASTptr);
239
240	if( root )
241	root->setFirstChild(RefAST(nullASTptr)); // don't leave any old pointers set
242
243	// link in children;
244	for( unsigned int i = 1; i < nodes.size(); i++ )
245	{
246	if ( nodes[i] == 0 ) // ignore null nodes
247	continue;
248
249	if ( root == 0 ) // Set the root and set it up for a flat list
250	root = tail = nodes[i];
251	else if ( tail == 0 )
252	{
253	root->setFirstChild(nodes[i]);
254	tail = root->getFirstChild();
255	}
256	else
257	{
258	tail->setNextSibling(nodes[i]);
259	tail = tail->getNextSibling();
260	}
261
262	if( tail ) // RK: I cannot fathom why this missing check didn't bite anyone else...
263	{
264	// Chase tail to last sibling
265	while (tail->getNextSibling())
266	tail = tail->getNextSibling();
267	}
268	}
269
270	return root;
271	}
272
273	/** Make a tree from a list of nodes, where the nodes are contained
274	* in an ASTArray object
275	*/
276	RefAST ASTFactory::make(ASTArray* nodes)
277	{
278	RefAST ret = make(nodes->array);
279	delete nodes;
280	return ret;
281	}
282
283	/// Make an AST the root of current AST
284	void ASTFactory::makeASTRoot( ASTPair& currentAST, RefAST root )
285	{
286	if (root)
287	{
288	// Add the current root as a child of new root
289	root->addChild(currentAST.root);
290	// The new current child is the last sibling of the old root
291	currentAST.child = currentAST.root;
292	currentAST.advanceChildToEnd();
293	// Set the new root
294	currentAST.root = root;
295	}
296	}
297
298	void ASTFactory::setASTNodeFactory( const char* factory_node_name,
299	factory_type factory )
300	{
301	default_factory_descriptor.first = factory_node_name;
302	default_factory_descriptor.second = factory;
303	}
304
305	#ifdef ANTLR_SUPPORT_XML
306	bool ASTFactory::checkCloseTag( ANTLR_USE_NAMESPACE(std)istream& in )
307	{
308	char ch;
309
310	if( in.get(ch) )
311	{
312	if( ch == '<' )
313	{
314	char ch2;
315	if( in.get(ch2) )
316	{
317	if( ch2 == '/' )
318	{
319	in.putback(ch2);
320	in.putback(ch);
321	return true;
322	}
323	in.putback(ch2);
324	in.putback(ch);
325	return false;
326	}
327	}
328	in.putback(ch);
329	return false;
330	}
331	return false;
332	}
333
334	void ASTFactory::loadChildren( ANTLR_USE_NAMESPACE(std)istream& infile,
335	RefAST current )
336	{
337	char ch;
338
339	for(;;) // for all children of this node....
340	{
341	eatwhite(infile);
342
343	infile.get(ch); // '<'
344	if( ch != '<' )
345	{
346	string error = "Invalid XML file... no '<' found (";
347	error += ch + ")";
348	throw IOException(error);
349	}
350
351	infile.get(ch); // / or text....
352
353	if( ch == '/' ) // check for close tag...
354	{
355	string temp;
356
357	// read until '>' and see if it matches the open tag... if not trouble
358	temp = read_identifier( infile );
359
360	if( strcmp(temp.c_str(), current->typeName() ) != 0 )
361	{
362	string error = "Invalid XML file... close tag does not match start tag: ";
363	error += current->typeName();
364	error += " closed by " + temp;
365	throw IOException(error);
366	}
367
368	infile.get(ch); // must be a '>'
369
370	if( ch != '>' )
371	{
372	string error = "Invalid XML file... no '>' found (";
373	error += ch + ")";
374	throw IOException(error);
375	}
376	// close tag => exit loop
377	break;
378	}
379
380	// put our 'look ahead' back where it came from
381	infile.putback(ch);
382	infile.putback('<');
383
384	// and recurse into the tree...
385	RefAST child = LoadAST(infile);
386
387	current->addChild( child );
388	}
389	}
390
391	void ASTFactory::loadSiblings(ANTLR_USE_NAMESPACE(std)istream& infile,
392	RefAST current )
393	{
394	for(;;)
395	{
396	eatwhite(infile);
397
398	if( infile.eof() )
399	break;
400
401	if( checkCloseTag(infile) )
402	break;
403
404	RefAST sibling = LoadAST(infile);
405	current->setNextSibling(sibling);
406	}
407	}
408
409	RefAST ASTFactory::LoadAST( ANTLR_USE_NAMESPACE(std)istream& infile )
410	{
411	RefAST current = nullAST;
412	char ch;
413
414	eatwhite(infile);
415
416	if( !infile.get(ch) )
417	return nullAST;
418
419	if( ch != '<' )
420	{
421	string error = "Invalid XML file... no '<' found (";
422	error += ch + ")";
423	throw IOException(error);
424	}
425
426	string ast_type = read_identifier(infile);
427
428	// create the ast of type 'ast_type'
429	current = create( ast_type, infile );
430	if( current == nullAST )
431	{
432	string error = "Unsuported AST type: " + ast_type;
433	throw IOException(error);
434	}
435
436	eatwhite(infile);
437
438	infile.get(ch);
439
440	// now if we have a '/' here it's a single node. If it's a '>' we get
441	// a tree with children
442
443	if( ch == '/' )
444	{
445	infile.get(ch); // get the closing '>'
446	if( ch != '>' )
447	{
448	string error = "Invalid XML file... no '>' found after '/' (";
449	error += ch + ")";
450	throw IOException(error);
451	}
452
453	// get the rest on this level
454	loadSiblings( infile, current );
455
456	return current;
457	}
458
459	// and finaly see if we got the close tag...
460	if( ch != '>' )
461	{
462	string error = "Invalid XML file... no '>' found (";
463	error += ch + ")";
464	throw IOException(error);
465	}
466
467	// handle the ones below this level..
468	loadChildren( infile, current );
469
470	// load the rest on this level...
471	loadSiblings( infile, current );
472
473	return current;
474	}
475	#endif // ANTLR_SUPPORT_XML
476
477	#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
478	}
479	#endif
480
481	/* Heterogeneous AST/XML-I/O ramblings...
482	*
483	* So there is some heterogeneous AST support....
484	* basically in the code generators a new custom ast is generated without
485	* going throug the factory. It also expects the RefXAST to be defined.
486	*
487	* Is it maybe better to register all AST types with the ASTFactory class
488	* together with the respective factory methods.
489	*
490	* More and more I get the impression that hetero ast was a kindoff hack
491	* on top of ANTLR's normal AST system.
492	*
493	* The heteroast stuff will generate trouble for all astFactory.create( ... )
494	* invocations. Most of this is handled via getASTCreateString methods in the
495	* codegenerator. At the moment getASTCreateString(GrammarAtom, String) has
496	* slightly to little info to do it's job (ok the hack that is in now
497	* works, but it's an ugly hack)
498	*
499	* An extra caveat is the 'nice' action.g thing. Which also judiciously calls
500	* getASTCreateString methods because it handles the #( ... ) syntax.
501	* And converts that to ASTFactory calls.
502	*
503	*
504	*/