[antlr-interest] Re: java.tree.g #(QUESTION expr expr expr)

[micheal_jor]

"rustydstone" wrote:
> Hi,
> 
> The following is slightly modified grammar from java.g and 
java.tree.g
> 
> conditionalExpression
> 	: logicalOrExpression 
>         ( QUESTION^ conditionalExpression COLON! 
conditionalExpression )?
> 	;
> 
> #(QUESTION q1:. q2:. q3:.)
> 
> When expression "(true || false)? 1 + 1 : 0 + 0" is processed the
> following q1, q2 and q3 ASTs are received (printed using 
toStringList()):
> 
> q1 ( || true false ) ( + 1 1 ) ( + 0 0 )
> q2 ( + 1 1 ) ( + 0 0 )
> q3 ( + 0 0 )
> 
> Why does q1 contain q2 and q3? Why does q2 contain q3? I somehow
> expected that the output would be like the following:
> q1 ( || true false )
> q2 ( + 1 1 )
> q3 ( + 0 0 )

toStringList() does just that - it prints the list of nodes starting 
from the specified node. The "list" being the node and it's following 
siblings.

In the same vein toStringTree() should do what you wanted - it should 
print the tree rooted at the specified node but not it's siblings[1*].

Cheers, 

Micheal

[1*] I have botched up this behaviour in ANTLR/C# by overriding 
ToStringTree() to print a nice tree-like representation and not a 
lisp-like representation of the specified tree only. This will be 
fixed and the nice tree-structured printing would be moved to new 
methods - do I hear any better monikers than ToNiceList()/ToNiceTree
() or even ToTreeList()/ToTreeTree()?


 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/