[antlr-interest] Re: Tree transformation

[Arnar Birgisson]

Hullo..

> -----Original Message-----
> From: Ric Klaren [mailto:klaren at cs.utwente.nl] 
>
> Nope ;) but there didn't seem to be a problem anymore. 

Not on my behalf no.. sorry for stirring you all up :o)

> I'm unsure atm wether Arnar's problems were all related to the 'lying'
> prettyprinter or that there's still some strange stuff.

Inside actions, I used just "label" to refer to subtrees. In that case,
the resulting tree was quite strange, as reported by the "truthful"
pretty-printer as well. After changing it to "#label", as Loring
suggested, it worked fine.

I understand the difference between #label and #label_in, but what does
label by it self mean? I haven't looked a the generated output yet so
maybe my question is stupid.

To clarify "quite strange" above, this is a simpilifaction of what
happened:

I have rules that transform

LIST
 |
expr1 - expr2 - ... - exprN

to

FUNC_CALL
 |
"mkPair" - parameters
             |
            expr1  - FUNC_CALL
                      |
                     "mkPair" - parameters
                                 |
                                expr2 - FUNC_CALL
                                         |
                                        etc...

But when the #(LIST (expr)*) subrule was labeled with some label, and
then referred to without any #-marks in front, the resulting tree was
like this

LIST
 |
expr1 - FUNC_CALL
         |
        "mkPair" - parameters
                    |
                   expr2 - ...

So obviously "some" transformation took place, but not on the top-level.

Again, I have this solved, so don't lose any sleep over this.

Arnar

ps. I could provide you with a grammar that exhibits this problem, but
all variable- and rulenames are in icelandic so you'd probably have a
hard time following it.


 

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