[antlr-interest] single-pass pattern matching "for free"?

[Terence Parr]

On Jan 15, 2006, at 12:50 PM, Sohail Somani wrote:
>> 2. patterns have no guarantee of coverage whereas a tree grammar  
>> does.
>
> What does this mean?

It means that there may be whole sections of syntax you have not  
dealt with in your list of translation rules.  A tree grammar on the  
other hand specifies the entire syntax of the tree and you know  
you've missed something when a rule has no translation actions.

Ter