[antlr-interest] insert after tree?

[Vaclav Barta]

Hi,

sorry for the late answer, but I had to publish the software first; :-) 
for programmatic transformations of SQL, I heartily recommend MacroScope 
(http://macroscope.sourceforge.net/). It's in C#, so probably not 
directly usable in your case, but IMHO still useful to see how your 
problem can be solved (in an ANTLR-nonspecific way - it was my first 
ANTLR project, so the architecture is quite conservative). ANTLR is used 
strictly for parsing. Its actions build an SQL syntax tree (not ANTLR 
AST, but a tree of custom typed objects - what MS calls an "object 
model"), and tree transformations (like adding an ESCAPE clause) are 
implemented separately, normally with visitors. I don't doubt ANTLR 
gurus could do tree transformations with much less code, but I don't 
regret starting simple - had enough ANTLR on my plate as it was...

	Bye
		Vasek

Geoff hendrey wrote:
> It's the first case you mention below.
> 
> More specifically, I need to recognize SQL "LIKE" expression trees from 
> within a SQL statement and add the text "ESCAPE '~'" after the LIKE 
> expression's tree. I have this in my grammar file.
> 
> likeExpression
>     :(concatenationExpression 'LIKE' concatenationExpression) ->^('LIKE' 
> concatenationExpression+ ESCAPE)     ;
> 
> I added the imaginary ESCAPE token, but I have not had any luck in my 
> Java trying to replace the imaginary escape token with the real text 
> "ESCAPE '~'". If only I could add a *real* token through my rewrite rule 
> above , I would be in business.
> 
> On PAge 176 of Terence's book it shows how to construct an imaginary 
> token with from a real token, but I don't have a real token to use (as 
> far as I can tell), which means I can't use the TokeRewriteStream with 
> the imaginary token, as far as I can tell.
> 
>  
> -geoff
> 
> 
> 
> 
> ----- Original Message ----
> From: Harald M. Müller <harald_m_mueller at gmx.de>
> To: Geoff hendrey <geoff_hendrey at yahoo.com>; antlr-interest at antlr.org
> Sent: Sunday, January 6, 2008 9:04:04 AM
> Subject: RE: [antlr-interest] insert after tree?
> 
> Sorry - I don't understand your question:
> - You have an AST?
> - you want to output it again as text?
> - but after some sub-AST of it, you want to have written some additional 
> text?
>  
> or
>  
> - You have an AST
> - you want to insert a node behind a certain sub-AST
> so that later tree parsers/walkers will see that additional node
>  
> Is it one of these two - or something differently?
>  
> Sorry for being a little bit slow ...
> Regards
> Harald
> 
>     ------------------------------------------------------------------------
>     *From:* antlr-interest-bounces at antlr.org
>     [mailto:antlr-interest-bounces at antlr.org] *On Behalf Of *Geoff hendrey
>     *Sent:* Sunday, January 06, 2008 9:22 AM
>     *To:* antlr-interest at antlr.org
>     *Subject:* [antlr-interest] insert after tree?
> 
>      From my Java program, I want to insert text after a *tree* not
>     after a token.
> 
>     I guess I am looking for a "TreeRewriteStream" as opposed to a
>     TokenRewriteStream.
> 
>     As a workaroud I tried creating an imaginary token in my grammar
>     file and using it to identify the rightmost side of a tree. Like this:
> 
>     a 'func' a ->^('func' a+ IMAGINARY)
> 
>     But then as I found out, the IMAGINARY Token doesn't seem to work
>     with TokenRewriteStream.insertAfter.
> 
>     Can anybody advise on how I can insert text immediately after a
>     particular tree? (The text is static so perhaps there is a way to do
>     it from the grammar file...)
> 
>