Tree API: offsets for String fields

[Emilian Bold]

Thank you!

PS: It would be great if JBS would allow me to register for email updates
on issues I care about...

--emi

On Thu, May 12, 2016 at 8:10 PM, Sundararajan Athijegannathan <
sundararajan.athijegannathan at oracle.com> wrote:

> Filed: https://bugs.openjdk.java.net/browse/JDK-8156866
>
> PS. Actually, I was wrong about MemberSelectTree - even internally nashorn
> IR node "AccessNode" maintains 'property' as a String. But, variables,
> functions have identifier nodes for names.
>
> Thanks,
>
> -Sundar
>
>
> On 5/12/2016 10:20 PM, Emilian Bold wrote:
>
> Assuming I don't need some special permissions to do that (do I?) I could
> expand the previous email and post it as an enhancement on
> https://bugs.openjdk.java.net
>
> But I'm also trying to understand the logic behind what you have.
>
> The way I see it any AST node has some underlying tokens so its offsets
> should be based on that.
>
> Take VariableTree. The Javadoc mentions:
>
> var name initializer ;
>
> but I assume the offset ranges are something like
>
> var [name = [initializer]] ;
>
> So, 'var' and whatever whitespace there is in between is ignored. The
> 'name' offsets are not explicit but may be inferred.
>
> (A similar problem with FunctionDeclarationTree.)
>
> What I would do with Variable Tree would be to have the offset ranges like:
>
> [var [name] = [initializer]]
>
> with the VariableTree covering everything ('var' too) and 'name' having a
> separate IdentifierTree.
>
> Continue/BreakTree/LabeledStatementTree are not really that
> important/used so if there is no internal info it's no big loss.
>
> --emi
>
>
> On Thu, May 12, 2016 at 7:19 PM, Sundararajan Athijegannathan <
> <sundararajan.athijegannathan at oracle.com>
> sundararajan.athijegannathan at oracle.com> wrote:
>
>> Hi,
>>
>> Thanks for your comments. Nashorn Parser API was modeled after similar
>> API provided by javac - for consistency sake and to leverage developer
>> familiarity.  For example, ContinueTree, MemberSelectTree of javac Tree
>> API:
>>
>>
>> https://docs.oracle.com/javase/8/docs/jdk/api/javac/tree/com/sun/source/tree/ContinueTree.html
>>
>>
>> https://docs.oracle.com/javase/8/docs/jdk/api/javac/tree/com/sun/source/tree/MemberSelectTree.html
>>
>> I agree that consistency should not result in API 'mistakes/gaps' being
>> propagated here.  BTW, labels are maintained as strings even
>> internally.  Member select property, Variable name , Function name etc.
>> are all identifiers and so it is possible to make API return
>> IdentifierTree objects. Will you please collect whatever you found and
>> file a bug/enhancement for Nashorn parser API?
>>
>> Thanks,
>>
>> -Sundar
>>
>>
>> On 5/12/2016 9:10 PM, Emilian Bold wrote:
>> > Hello,
>> >
>> > It's really important for a Javascript editor to know the offsets of
>> each
>> > syntax tree node and of whatever the node contains (I'm not really
>> saying
>> > tokens but... constituent parts and keywords are the minimum).
>> >
>> > So it would be great to provide or document how offsets are to be
>> computed
>> > for the String fields from the Nashorn Tree API.
>> >
>> > (Ideally the API could also be changed to use an IdentifierTree or some
>> > other Tree subclass which provides the start/endPosition.)
>> >
>> > A few examples:
>> >
>> > * MemberSelectTree has a String getIdentifier. Since I *assume* that the
>> > MemberSelectTree.getEndPosition is right after the identifier, I have to
>> > subtract the identifier length to get the identifier start offset.
>> >
>> > * VariableTree has a String getName(). It seems to me that
>> > VariableTree.getStartPosition is the 'name' startPosition. This also
>> means
>> > you cannot really know where 'var' actually is -- it could be on another
>> > line altogether; it's also odd to me that 'var' is outside the [start,
>> end]
>> > range for the VariableTree.
>> >
>> > * ContinueTree and BreakTree both have a String getLabel
>> >
>> > * LabeledStatementTree has a String getLabel
>> >
>> > * FunctionExpressionTree and FunctionDeclarationTree both have a String
>> > getName but I'm not sure how the offset for that is computed. Also not
>> sure
>> > how the offset of the 'function' keyword would be computed.
>> >
>> > Could somebody explain this to me? I'll make a nice list for future
>> > reference.
>> >
>> > --emi
>>
>>
>
>