Re: [cdt-core-dev] C++ Parser

[John Camelon <jcamelon@xxxxxxxxxx>]

Our AST is incomplete when it comes to statements.
 It is something we will need to address in the future once we get
a bit more performant and scalable.  

Thanks
JohnC

cdt-core-dev-admin@xxxxxxxxxxx wrote on 07/07/2004
05:54:31 AM:

> I want to use the parser to give me details of where C/C++ 
> statements are, however I have so far failed to penetrate the AST
> with an instance of the ISourceElementRequestor (See code at the 
> end).  Here is an example of what I’d like as information, take
the 
> following C code:
>  
> 1: int main(int argc, char argv[])
> 2: {
> 3:  if (argc == 0) {
> 4:    printf("You didn't pass
in any arguments");
> 5:    return -1;
> 6:  }
> 7:  else {
> 8:    printf("You passed in %d
args\n",argc);
> 9:    return 1;
> 10:  }
> 11:}
>  
> I am particularly interested in understanding
that the ‘If’ keyword 
> is on line 3, the condition statement is also on line 3, the ‘else’
> keyword is on line 7.  Then I need to know the details of the
‘then’
> code block and the ‘else’ code block.
>  
> I traced through the parser code and it seems
that it should be 
> possible to get this information, but it seems that the line number
> is not stored, or it maybe stored if a new scope is generated for
> the ‘if’.  For those not familiar with the code this token
reading 
> etc. is all happening in the package cdt.internal.core.parser. and
> cdt.internal.core.parser.ast.
>  
> So right now my ISourceElementRequestor gets
the codeBody call back 
> for the ‘then’ block and the ‘else’ block, but I don’t seem to
be 
> able to determine  the details of the statements within the code
> bodies, nor the location of syntactic keywords.
>  
> Could someone please shed some light on this
for me?  I am assuming 
> that this kind of thing is already done for the editor that 
> highlights keywords in the source files, but I am not sure.
>  
> Any insights will be very much appreciated.  
>  
> Jason
>  
> PS: Below is the code I’m using.
>  
> class CMySourceElementRequestor extends StructuralParseCallback
> {
>     private ParserMode mode = ParserMode.COMPLETE_PARSE;
>  
>             private
void addElement (IASTDeclaration element){
>              
          if(inclusionLevel == 0){
>              
                     
if( currentScope instanceof ASTScope )
>              
                     
            ((ASTScope)
> currentScope).addDeclaration(element);
>              
                     
else if( currentScope instanceof
> ASTLinkageSpecification )
>              
                     
            
> ((ASTLinkageSpecification)currentScope).addDeclaration( element );
>              
          }
>             }
>             
>             private
void enterScope(IASTNode node){
>              
          if(node instanceof IASTScope){
>              
                     
if(node instanceof ASTScope){
>              
                     
            ((ASTScope)node).
> initDeclarations();
>              
                     
}
>              
                     
pushScope((IASTScope)node);
>              
          }
>             }
>  
>             private
void exitScope(IASTNode node){
>              
          if(node instanceof IASTScope){
>              
                     
popScope();
>              
          }
>             }
>             
>             private
void pushScope( IASTScope scope ){
>              
          scopeStack.addFirst( currentScope );
>              
          currentScope = scope;
>             }
>             
>             private
IASTScope popScope(){
>              
          IASTScope oldScope = currentScope;
>              
          currentScope = (scopeStack.size() >
0 ) ? 
> (IASTScope) scopeStack.removeFirst() : null;
>              
          return oldScope;
>             }
>             
>             public
void enterFunctionBody( IASTFunction function )
>             {
>              
          System.out.println("Enter function");
>              
          if(function.getOwnerTemplateDeclaration()
== null)
>              
                     
addElement(function);
>              
          else if(function.
> getOwnerTemplateDeclaration() instanceof IASTTemplateDeclaration)
>              
                     
> addElement((IASTTemplateDeclaration)function.getOwnerTemplateDeclaration());
>             }
>             
>             public
void exitFunctionBody( IASTFunction function )
>             {
>              
          System.out.println("Exit function");
>              
          function.setHasFunctionBody( true );
>             }
>             
>             public
void enterCodeBlock( IASTCodeScope scope )
>             {
>              
          System.out.println("Enter Code
Block");
>              
          enterScope(scope);
>             }
>             
>             public
void exitCodeBlock( IASTCodeScope scope )
>             {
>              
          System.out.println("Exit Code Block");
>              
          exitScope(scope);
>             }
>  
>             public
void enterCompilationUnit( IASTCompilationUnit 
> compilationUnit )
>             {
>              
          System.out.println("Enter Compilation
Unit");
>              
          enterScope(compilationUnit);
>             }
>              
          
>             public
void exitCompilationUnit( IASTCompilationUnit 
> compilationUnit )
>             {
>              
          System.out.println("Exit Compilation");
>              
          exitScope(compilationUnit);
>              
          this.compUnit = compilationUnit;
>             }
>  
>             /**
>              *
@param finalPath
>              *
@return
>              */
>             public
CodeReader createReader(String finalPath, 
> Iterator workingCopies )
>             {
>              
          return InternalParserUtil.createFileReader(
> finalPath );
>             }
>             /**
>              *
The parser asks the client if it wishes to time out 
>              *
in case it is taking more than the expected time.
>              *
@return
>              */
>             public
boolean parserTimeout()
>             {
>              
          return false;
>             }
> }
>  
> /**
>  * @author jason
>  *
>  * TODO To change the template for this
generated type comment go to
>  * Window - Preferences - Java - Code Style
- Code Templates
>  */
> public class Test {
>  
>             public
static void main(String[] args) {
>              
          IScanner myIScanner;
>              
          IParser myIParser;
>              
          CMySourceElementRequestor mySourceElementRequestor;
>              
          
>              
          try
>              
          {
>              
                     
mySourceElementRequestor = new 
> CMySourceElementRequestor();
>              
                     
myIScanner = ParserFactory.
> createScanner("c:\\temp\\test.c",new ScannerInfo(),ParserMode.
> COMPLETE_PARSE,ParserLanguage.C, mySourceElementRequestor, null,null);
>              
                     
myIParser = ParserFactory.
> createParser(myIScanner, mySourceElementRequestor, ParserMode.
> COMPLETE_PARSE, ParserLanguage.C,null);
>              
                     
if (myIParser.parse() == true)
>              
                     
{
>              
                     
            System.out.
> print("Parse successful");
>              
                     
}
>              
                     
else
>              
                     
{
>              
                     
            System.out.
> print("Parse unsuccessful");
>              
                     
}
>              
          }
>              
          catch (IOException e)
>              
          {
>              
                     
return;
>              
          }
>             }
> }