ASTFactory.cpp

/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/license.html
 *
 * $Id$
 */
 
#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.
 *
 *
 */