[antlr-interest] How to handle? Synthetic token?

[James Ladd]

Maybe I have answered my own question:

temporaries
    :       '||'
    |       '|' temporaryVariables '|'
    |       '|' temporaryVariables errorYouMissedClosingPipe
    ;

<snip>

errorYouMissedClosingPipe
    :    ~('|' | NAME)
    ;

When I use the NOT token I get the correct parsing.
For example, this is not correct:    | foo bar [

*note: the things that are not '|' or NAME need to be matched as well.
So in the example I gave '[' has to be a matched token.

My question not is:   Is this an ok approach / thing to do?

Rgs, James.

From: james_ladd at hotmail.com
To: antlr-interest at antlr.org
Subject: How to handle? Synthetic token?
Date: Tue, 21 Dec 2010 16:15:11 +1100








Hi All,

I'm wondering if it is possible to add a rule or token to help trap errors?
I have the following:

temporaries
    :    '||'
    |    '|' temporaryVariables '|'
    ;

Which is fine and the allowed cases, however, I'd like to the following:

temporaries
    :    '||'
    |    '|' temporaryVariables '|'
    |    '|' temporaryVariables errorYouMissedClosingPipe
    ;

Possibly by defining errorYouMissedClosingPipe as a rule or token that matches anything but the '|'.

Is this possible and could someone provide an example or a link to a page that describes this?

Rgs, James.