[antlr-interest] How can I maintain the order in the tree?

[Daniels, Troy (US SSA)]

I think something like this should work.

 

parent: child -> ^(Parent child);

 

child: (childA | childB | childC) child | /* nothing */ ;

 

Multiple calls to child will build up the tree in the right order.  You
probably also need something to put the term that matched into a tree,
but this is the basic idea.

 

Troy

 

  _____  

From: antlr-interest-bounces at antlr.org
[mailto:antlr-interest-bounces at antlr.org] On Behalf Of Gabriel Petrovay
Sent: Wednesday, March 18, 2009 1:03 PM
To: antlr-interest
Subject: [antlr-interest] How can I maintain the order in the tree?

 

Hi all,

Take this example:

tokens {
Parent;
}

parent : (childA | childB | childC)*
    -> ^(Parent childA* childB* childC*)
  ;

if I provide as input:
childB childC childA childB

the tree will order them as defined in the rule and return the following
tree:
^(Parent childA childB childB childC)

How can I define a tree that maintains this order?
e.g. I want to get: ^(Parent childB childC childA childB)


Thanks!

-- 
MSc Gabriel Petrovay
MCSA, MCDBA, MCAD
Mobile: +41(0)787978034

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