Re: [abc-users] Compilation error with intertypes when using the abc weaver

Ok this was a simple one, it seems. Should be fixed in SVN revision 7473.

Eric

2009/5/19 Eric Bodden <eric.bodden_at_mail.mcgill.ca>:
> Hi all.
>
> I looked into this a bit.
>
> Indeed it's a bug in the polyglot frontend. It has nothing to do with
> the "$" sign; the bug even occurs without it. Henrique, you should be
> able to compile your code by adding "-ext abc.ja" to your command
> line. This tells abc to use the newer JastAdd-based frontend instead.
> At least your little example compiles fine with that frontend. I will
> see if I can fix the bug in the polyglot-based frontend nevertheless.
>
> Eric
>
> 2009/5/19 Eric Bodden <eric.bodden_at_mail.mcgill.ca>:
>> Oh, I guess that explains that then. Thanks a lot for pointing this
>> out Pavel. Guess we have been teaching something wrong then in our
>> compiler class for ages :P
>>
>> Were you guys aware of this when you first implemented abc? I would be
>> surprised if abc did not internally make some assumptions about
>> certain $ signs being or not being part of certain identifiers.
>>
>> Eric
>>
>> 2009/5/19 Pavel Avgustinov <pavel_at_comlab.ox.ac.uk>:
>>> Hi Eric,
>>>
>>> Thanks for taking the time to look into this.
>>>
>>> I was intrigued by your diagnosis, so I consulted the Java Language
>>> Specification. The relevant section is:
>>>
>>> http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#3.8
>>>
>>> This states, among other interesting and useful things,
>>>
>>> "The Java letters include uppercase and lowercase ASCII Latin letters A-Z
>>> (\u0041-\u005a), and a-z (\u0061-\u007a), and, for historical reasons, the
>>> ASCII underscore (_, or \u005f) and dollar sign ($, or \u0024). The $
>>> character should be used only in mechanically generated source code or,
>>> rarely, to access preexisting names on legacy systems."
>>>
>>> The $ character is perfectly legal in Java identifiers (in fact you can have a
>>> variable called "$"), but is usually omitted from introductory texts because
>>> it is used for compiler-generated names (cf. this$0, names for nested classes,
>>> accessor methods and advice names) and if human programmers avoid it, the
>>> probability of accidental name clashes is reduced.
>>>
>>> - P
>>>
>>> On Tuesday 19 May 2009 12:28:34 Eric Bodden wrote:
>>>> >     Yes, surprisingly both alow that. In relation to Java, I first saw
>>>> > such a situation in the instrumented source code
>>>> >     generated by JML. In addition, since a valid AspectJ program is also
>>>> > a valid Java program, we can use "$" in AspectJ
>>>> >     programs as well, for instance, in intertype declarations (as in
>>>> > previous email).
>>>>
>>>> Yes, there's two different things: identifiers in Java source code and
>>>> identifiers in the bytecode. $ is allowed in bytecode but not usually
>>>> on the source level. The AspectJ language definition states that
>>>> AspectJ identifiers are just Java identifiers. Therefore AspectJ
>>>> compilers should not actually parse your example program. I have
>>>> raised a bug against ajc to clarify that...
>>>> https://bugs.eclipse.org/bugs/show_bug.cgi?id=276794
>>>>
>>>> Anyway, I have not yet had the time to look into this but I suspect
>>>> that abc may get confused by those names. I will see if I can find
>>>> some time to dig a bit deeper into the problem today.
>>>>
>>>> Eric
>>>
>>>
>>>
>>>
>>
>>
>>
>> --
>> Eric Bodden
>> Sable Research Group, McGill University
>> Montréal, Québec, Canada
>>
>
>
>
> --
> Eric Bodden
> Sable Research Group, McGill University
> Montréal, Québec, Canada
>

-- 
Eric Bodden
Sable Research Group, McGill University
Montréal, Québec, Canada