[antlr-interest] Error nodes created upon syntax error

[Terence Parr]

On Dec 3, 2007, at 5:05 AM, Johannes Luber wrote:
> It makes sense, but what about single deletion/insertion in normal  
> mode?

Well, i've been thinking.  I realize now that that mode is only of  
academic interest.  How can you execute actions without putting in  
guards against all possible input syntax errors?  That's what we call  
a parser. ;)  So, upon error in a rule, you must execute no further  
actions and immediately report error, recover, and return.

> How do we deal with an ERROR node in the next grammar? Or is then  
> there
> a way to emit an error message during the construction of the AST?

Well, presumably, you wouldn't pass the tree along to another  
grammar...it is malformed.

Ter