[antlr-interest] Re: Layout processing
lachinois2002
lachinois at hotmail.com
Tue Jan 13 13:45:31 PST 2004
Hi Loring, thanks for your pointer it has proven very usefull.
However, it does not completely solve my problem... Maybe Terence
can give me some further cues when he has some time. The problem
arrises when I want to convert a document to SGML and the DTD
specifies inclusions (that is elements that can appear anywhere
between other elements).
Here is a quick example of what I would like to accomplish.
For example, lets say I have a rule:
a: b c
It should have been written like this if we wanted to consider
possible inclusions:
a: b (inc)* c
Now, if I (only) had:
a: b c? d?
Things get much more messy to avoid running into infinite lookahead
problems... (imagine a fully fledged rule)
a: (b (inc)* c)=>
(
b (inc)*
(
(c (inc)* d) =>
(
c (inc)* d
)
|
d
)
)
|
(b (inc)* d)=>
(
b (inc)* d
)
|
b
I could write a pre-processor that would rewrite all my rules with
all the various combinations *, + and | that can arrise. However
this is a big task...
Dont forget that sometimes in the DTD inc can appear explicitly.
I'm not sure I can accomplish something similar using actions and
overriding default lexer/parser/tree/token behavior...
Daniel Shane
--- In antlr-interest at yahoogroups.com, "lgcraymer" <lgc at m...> wrote:
> Daniel--
>
> Ter's busy moving into his new domicile or he would probably
answer. Check out his "preserving token sequence" stuff
>
<http://www.antlr.org/article/preserving.token.order/preserving.token
.order.tml>; my impression is that may help.
>
> --Loring
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