[antlr-interest] Re: Trouble modifying Java source w/ ANTLR
cliftonccraig
ccc at icsaward.com
Fri Feb 20 13:41:18 PST 2004
Last Stretch:
I have everything working wonderfully and now I'm in the home stretch.
I need a clever way of doing one of the following:
Either remove an inserted version string after detecting an already
coded one. (RewriteEngine.rollback()? How does this work?)
Or inserting the version strings at all pre-recorded classBlock
indices after reaching end of file and not finding them. I perferr the
1st option if possible as it seems cleaner. However I think I might be
able to hack the second option. Any suggestions?
Thanx in advance,
Cliff
--- In antlr-interest at yahoogroups.com, "cliftonccraig" <ccc at i...> wrote:
> I think I finally got it! I just start with the index of the
> identifier under the variableDeclarator rule and advance past the
> white space to get my starting point. I then advance to the SEMI token
> to get my stopping point and viola! Heres what I have so far:
>
> variableDeclarator![AST mods, AST t]
> : id:IDENT d:declaratorBrackets[t] v:varInitializer
> {
> //*CCC- scan here for version indentifiers and replace the
> initializer with the new value.
> if(id.getText().equals("VERSION"))
> {
> int start = ((TokenWithIndex)id).getIndex() + 1, stop = start;
> TokenWithIndex next = engine.getToken(start);
> //Skip white space...
> while(next.getType()==WS) {start++; next =
> engine.getToken(start);}
> //Advance to SEMI identifier...
> stop = start;
> while(next.getType()!=SEMI) {stop++; next =
> engine.getToken(stop);}
> stop--; //Don't include the SEMI in the replacement.
> engine.replace(start,stop,"= \"MODIFIED!\"");
> }
> #variableDeclarator = #(#[VARIABLE_DEF,"VARIABLE_DEF"], mods,
> #(#[TYPE,"TYPE"],d), id, v);
> }
> ;
>
> Whew! I thought this would've ended up to be over a week-long project
> but Ive only spent a couple days. All I need now is to parameterize
> the whole thing so it can be a usefule re-usable component. Thnax
> everyone!
>
> Cliff
>
>
> --- In antlr-interest at yahoogroups.com, "cliftonccraig" <ccc at i...> wrote:
> > Thank you everyone,
> >
> > The thing is I'm new to both grammar engines and sed. So to me it's
> > the lesser of two evils. I've gotten a little further in this as I've
> > been able to figure out the Java grammar a little more. So far I've
> > narrowed where my mods go to the variableDeclarator rule. This is what
> > I have so far:
> > variableDeclarator![AST mods, AST t]
> > : id:IDENT d:declaratorBrackets[t] v:varInitializer
> > {
> > //*CCC- scan here for version indentifiers and replace the
> > initializer with the new value.
> > if(id.getText().equals("VERSION"))
> > {
> > int start = ((TokenWithIndex)id).getIndex() + 1,
> > stop = start + #d.getNumberOfChildren() +
> > #v.getNumberOfChildren() - 1;
> > //System.out.println("Starting from " + start + " ending at
> > " + stop);
> > //System.out.println("prevToken ==" + prevToken);
> > engine.replace(start,stop,"\"MODIFIED!\"");
> > }
> > #variableDeclarator = #(#[VARIABLE_DEF,"VARIABLE_DEF"], mods,
> > #(#[TYPE,"TYPE"],d), id, v);
> > }
> > ;
> >
> > It gets a little hairy because the "stuff" I want to replace is not
> > defined as tokens in the grammar, rather they're defined as parser
> > rules. The rewrite engine example shows replacment using tokens but I
> > don't know how to get an accurate token count from the two AST objects
> > at this point. I know the one (#d) is really just a place holder as
> > there will be no array declaration here but the other does not seem to
> > be yielding the right amount of child nodes. I think I'm at a
> > misunderstanding here (child-nodes != tokens)? When I run everything
> > with my above mods I get something like the following:
> > public final static String VERSION"MODIFIED!"= "2.3";
> > where it clearly looks like the node count is evaluating to one and
> > the token count is much higher (accomodating for whitespace and such).
> > I don't want to hard code this because the version assignment may not
> > always be a simple assignment. It could be an expression and I want to
> > be able to replace the whole expression. Could you steer me in the
> > right direction here?
> >
> > Cliff
> >
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