State index

[zakaria jaiathe]

Maybe it's too easy, but I simply can't find how can I get the state index given a token name.

For the parser rules I use 

ATNState states[] = g.atn.ruleToStartState;
Rule r = g.getRule(startRule);
index = r.index;
state = states[index];

But I can't use this in the lexer grammar because the only existing rules are the parser rules.

Thanks a lot.

[Terence Parr]

There is an array of

On Mar 21, 2014, at 8:17 AM, zakaria jaiathe <z.ja...@gmail.com> wrote:

Maybe it's too easy, but I simply can't find how can I get the state index given a token name.

For the parser rules I use 

ATNState states[] = g.atn.ruleToStartState;
Rule r = g.getRule(startRule);
index = r.index;
state = states[index];

 the index is a rule index not a state index. you will have to access the ATN state within the rule. I can remember what is available at the moment; take a look at the API or the source.

But I can't use this in the lexer grammar because the only existing rules are the parser rules.

Thanks a lot.

 You will have to look at the source to see what data structures are available in the LexerATNSimulator.  I didn’t anticipate making the states available.

 what are you trying to do?

Ter

[Sam Harwell]

There is no direct relation between token types and lexer rule indexes (and thus no relation to states in the ATN). Lexer rules frequently contain the type, more, or skip commands, or even custom embedded actions to alter the type produced for a rule.

 

Depending on what you are trying to accomplish (you didn’t specify), you’ll need to do things some other way.

 

Sam

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[zakaria jaiathe]

Hi,

Thank you for your answers. What I want to do is to re-implement the Random Phrase class in Antlr4. At this stage, I want to generate a random value of a token given its name.

Regards

Zak