Fwd: [antlr-interest] Jump over nodes in tree construction

[Bryan Ewbank]

[[Sending this to the list so that it's in the collective]]

Another option that should work with a bit less C++ goo...

  /**
   * first alternative discards extra EXPR node;
   * second alternative is passthru.
   */
  unbrace_expr!
  : ( EXPR ) => #( EXPR e1:. )   { ## = #e1; }
  | e2:.  { ## = #e2; }
  ;

As a side question, might you prefer a recursive definition to remove
redundant nodes from the tree?

  /**
   * first alternative rips out all EXPR nodes;
   * second alternative restores one level of same.
   */
  unbrace_expr!
  : ( EXPR ) => #( EXPR e1:unbrace_expr )   { ## = #e1; }
  | e2:.  { ## = #( #[EXPR,"EXPR]", #e2); }
  ;

Hope this helps.  I've learned that if I see getType() or
getFirstChild() in my C++, it means I need to refactor some of that
into ANTLR.

On Tue, 15 Mar 2005 06:11:08 +0000, marc schellens
<m_schellens at hotmail.com> wrote:
> unbrace_expr!
>       : ex:expr
>               {
>            // remove last pair of braces
>            if( #ex->getType()==EXPR)
>                #unbrace_expr= #( NULL, ex->getFirstChild());
>            else
>                #unbrace_expr= #( NULL, ex);
>               }