[antlr-interest] Re: Tree transformation

[lgcraymer]

Arnar--

That sounds like something may have been broken in 2.7.2.  It sounds 
very much like you are referencing the input tree, and that 
shouldn't be happening.

Ric--Any thoughts?

--Loring


--- In antlr-interest at yahoogroups.com, "Arnar Birgisson" 
<arnarb at o...> wrote:
> Hi there,
> 
> I tried putting # in front of list, which made it worse. Before, 
only
> the first level of the subtree wasn't being processed, after 
putting #
> in front of the label name, it seems that the whole subtree is not
> transformed. The result is just as if I copied the input-tree as-
is.
> 
> Arnar
> 
> > -----Original Message-----
> > From: lgcraymer [mailto:lgc at m...] 
> > Sent: 16. nóvember 2003 20:27
> > To: antlr-interest at yahoogroups.com
> > Subject: [antlr-interest] Re: Tree transformation
> > 
> > 
> > Arnar--
> > 
> > Take a look at <http://www.antlr.org/doc/trees.html#Action%
> > 20Translation>.  ANTLR labels get transformed during 
translation; if 
> > I remember correctly, #label translates to labelAST and 
#label_in to 
> > label.  You are probably reusing the input tree by accident 
here.  
> > Try replacing list with #list in the action.
> > 
> > --Loring
> > 
> > --- In antlr-interest at yahoogroups.com, "Arnar Birgisson" 
> > <arnarb at o...> wrote:
> > > Hello again..
> > > 
> > > I solved this problem by rewriting the transformation so that 
it 
> > worked
> > > without the !. However, I keep hitting this wall in other 
places, 
> > and
> > > now I'm completely stuck. Consider those (simplified) 
constructs 
> > in my
> > > language
> > > 
> > > f -> procedure()
> > > var x
> > > body
> > >   expression1,
> > >   block
> > >     x := \incr x,
> > >     \print [1,2,3]
> > >   endblock,
> > >   x := \incr ,
> > >   \print [1,2,3]
> > > endbody
> > > 
> > > Now.. the expressions "\incr x" and "[1,2,3]" have such trees:
> > > 
> > > #([OPERATOR,"incr"] x)
> > > #([LIST,"["] #([EXPR_LIST] 1 2 3) )
> > > 
> > > and I have rules in my tree transformer that changes them to 
the
> > > equivalent of the expressions "incr(x)" (function call) and
> > > "mk_pair(1,mk_pair(2,mk_pair(3,[])))". This transformation 
works 
> > very
> > > well for the second pair of those expressions.
> > > 
> > > Now I want to make a transformation for turning
> > > 
> > > BLOCK
> > >  | 
> > > EXPR_LIST
> > >  |
> > > expr1 - expr2 - ... - exprN
> > > 
> > > to
> > > 
> > > expr1 - expr2 - ... - exprN.
> > > 
> > > For this I have the rule alternative
> > > 
> > > |! #(BLOCK list:expr_list)
> > > 	{
> > > 		## = list->getFirstChild();
> > > 	}
> > > 
> > > This seems to work except that the transformations inside this 
> > instance
> > > of expr_list don't get executed. Therefore, the transformation 
of 
> > the
> > > code above is applied only to the second pair of afformentioned
> > > expressions.
> > > 
> > > I'm using exactly the same rule (expr_list) to traverse the 
list of
> > > expressions whether they are inside the procedure body, or 
inside a
> > > block. I'm stumped!
> > > 
> > > If I remove the ! I get two copies of the subtree, one where
> > > transformations have been applied, and one where they havent...
> > > 
> > > Am I doing something terribly wrong or is this unexpected 
> > behaviour?
> > > 
> > > Arnar
> > > 
> > > 
> > > > -----Original Message-----
> > > > From: mzukowski at y... [mailto:mzukowski at y...] 
> > > > Sent: 14. nóvember 2003 18:39
> > > > To: antlr-interest at yahoogroups.com
> > > > Subject: RE: [antlr-interest] Tree transformation
> > > > 
> > > > 
> > > > Hard to tell.  I recommend using -traceParser and following 
> > > > through the code
> > > > to see what's happening.
> > > > 
> > > > Monty
> > > > 
> > > > -----Original Message-----
> > > > From: Arnar Birgisson [mailto:arnarb at o...] 
> > > > Sent: Friday, November 14, 2003 7:24 AM
> > > > To: antlr-interest at yahoogroups.com
> > > > Subject: [antlr-interest] Tree transformation
> > > > 
> > > > Hello..
> > > > 
> > > > I'm having some trouble I can't figure out, possibly because 
I'm 
> > doing
> > > > something stupid.
> > > > 
> > > > I have this rule in a tree parser for transforming loops:
> > > > 
> > > > loop_stmt
> > > > 	: #(L_LOOP stmt_list)
> > > > 	| #(L_WHILE expr stmt_list)
> > > > 	|! #(L_FOR init:stmt_list test:expr incr:stmt_list
> > > > body:stmt_list)
> > > > 		{
> > > > 			/* this changes "for" loops 
to "while" loops 
> > */
> > > > 			antlr::RefAST newbody;
> > > > 			antlr::RefAST lastBodyStmt =
> > > > body->getFirstChild();
> > > > 			if (antlr::nullAST == lastBodyStmt) {
> > > > 				newbody = incr;
> > > > 			} else {
> > > > 				while (antlr::nullAST !=
> > > > lastBodyStmt->getNextSibling())
> > > > 					lastBodyStmt =
> > > > lastBodyStmt->getNextSibling();
> > > > 	
> > > > lastBodyStmt->setNextSibling(incr->getFirstChild());
> > > > 				newbody = body;
> > > > 			}
> > > > 			antlr::RefAST l = #
([L_WHILE,"while"], test,
> > > > newbody);
> > > > 			antlr::RefAST lastInitStmt =
> > > > init->getFirstChild();
> > > > 			if (antlr::nullAST == lastInitStmt) {
> > > > 				## = l;
> > > > 			} else {
> > > > 				while (antlr::nullAST !=
> > > > lastInitStmt->getNextSibling())
> > > > 					lastInitStmt =
> > > > lastInitStmt->getNextSibling();
> > > > 				lastInitStmt->setNextSibling
(l);
> > > > 				## = init->getFirstChild();
> > > > 			}
> > > > 		}
> > > > 	;
> > > > 
> > > > Now, stmt_list is a simple rule
> > > > 
> > > > stmt_list
> > > > 	: #(STMT_LIST (stmt)*)
> > > > 	;
> > > > 
> > > > and the stmt rule is a big rule, with one alternative being 
this
> > > > (note that in my language there is no difference between 
> > > > statements and
> > > > expressions):
> > > > 
> > > > 	|! #(OPERATOR s1:expr s2:expr)
> > > > 		{
> > > > 			/* this changes "x <op> b" to the 
function 
> > call
> > > > "<op>(x,y)"
> > > > 			#OPERATOR->setType(ID);
> > > > 			## = #([OPEN_PAR,"("], ADGERD,
> > > > #([stmt_list,"params"], s1, s2));
> > > > 		}
> > > > 
> > > > Now, this alternative successfully transforms operator 
> > statements to
> > > > function alls when they are top level statements in 
functions 
> > > > (accessed
> > > > throught stmt_list), but when they're in a for-loop body 
> > > > (named "body")
> > > > in the above rule, no transformation takes place, i.e. #
> > (OPERATOR expr
> > > > expr) is left as is.
> > > > 
> > > > I've tried removing the ! in the for-loop rule but that 
doesn't 
> > help..
> > > > the transformation doesn't take place.
> > > > 
> > > > Any ideas?
> > > > 
> > > > Arnar
> > > > 
> > > > 
> > > >  
> > > > 
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> > > > 
> > > > 
> > > >  
> > > > 
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> > > > 
> > > >
> > 
> > 
> >  
> > 
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> > 
> >


 

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