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Re: [cdt-dev] Can't find IASTExpressionList any more more in the CDT AST

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On 22 April 2010 08:56, Schorn, Markus <Markus.Schorn@xxxxxxxxxxxxx> wrote:
> Hi,
> up to 6.0 the arguments for a function call were returned by
> IASTFunctionCallExpression.getParameterExpresssion()
> like this:
> * null, when there is no argument
> * IASTExpression for a single argument
> * IASTExpressionList for multiple arguments
> This API was not the best choice:
> * The name is wrong (an argument is not a parameter) .
> * It's not obvious and it's not straight forward to figure out how many
> arguments there are.
> * It overloads the meaning of IASTExpressionList, which also represents
> expressions using the comma-operator.
> Now in c++0x the argument list for a function call can contain initializer
> lists, which are no expressions. Therefore,
> the argument list can no longer be expressed as an IASTExpression. So, this
> was a good time to deprecate
> IASTFunctionCallExpression.getParameterExpression().
> While the ast-nodes themselves are backwards compatible in that an
> IASTExpressionList is created
> when you call the deprecated method
> IASTFunctionCallExpression.getParameterExpression(), a visitor will
> follow the new AST-Tree.
> Markus.
> ________________________________
> From: cdt-dev-bounces@xxxxxxxxxxx [mailto:cdt-dev-bounces@xxxxxxxxxxx] On
> Behalf Of Beth Tibbitts
> Sent: Wednesday, April 21, 2010 11:26 PM
> To: CDT General developers list.
> Subject: [cdt-dev] Can't find IASTExpressionList any more more in the CDT
> Importance: Low
> I'm debugging some of our PTP static analysis that makes heavy use of the
> The original author did a lot of 'instanceof' to discover things.
> CDT 7.0 is giving a different behavior than CDT 6.0 did.
> A particularly nasty bug now, it turns out, seems to be because a value that
> comes from a parameter list
> isn't populated, probably because as this part of the program is descending
> down part of the AST,
> it expects to find an IASTExpressionList node, and find the parameter in
> there.
> But it never finds it.
> In a visitor,
> int visitor(IASTExpressions expr){
> ...
> if(expr instanceof IASTExpressionList){ // this is never true
> ... do something
> }
> }
> I seem to remember some things related to parameters being deprecated,
> but IASTExpressionList itself isn't itself deprecated, and I never find one.
> Anybody know what I should be looking for instead of this?
> AHA.....
> If I look at the nodes as they hit the visitor, it sort of looks like
> the AST now no longer has an IASTExpressionList node at all.
> I see the IASTFunctionCallExpression and then I see the IASTIDExpression for
> the function name and two UnaryExpressions (one for each arg),
> not wrapped in an IASTExpressionList as it was before.
> In fact, the DOM AST view shows this quite clearly. Should have looked more
> closely at (this part of) that sooner.
> Nothing like composing a problem for a mailing list post to point the
> problem out to yourself.
> I guess I'll just grab the parameters from the expressions that follow the
> IASTIDexpression for the call name.
> If anyone has more introspection I should be seeing here, please let me
> know.
> I am sort of curious why it changed.
> ...Beth
> Beth Tibbitts
> Eclipse Parallel Tools Platform
> IBM STG Communications Protocols and Tools
> Mailing Address: IBM Corp., Coldstream Research Campus, 745 West New Circle
> Road, Lexington, KY 40511
> _______________________________________________
> cdt-dev mailing list
> cdt-dev@xxxxxxxxxxx

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