[antlr-interest] $FIRST $FOLLOW

[Ulrich Frank]

Hello InterestGroup.

I've the following problem and perhaps you can help me. I hope so. I 
have to build an application which should recognice some kind of OQL 
(Object Query Language) grammar. Ok, thats not the problem. I wrote an 
appopriate grammar. If I parse a sample String like "select attr from 
obj" I get the information if the String respects the OQL grammar or not.

But what i want to do is the following: When I write the String "Select 
sdf" and push then CTRL-Space there shoult be a context menu which shows 
me all the posibilities which are correct at this position (just like in 
Eclipse f.e.). In this case  only "from" should be shown. If I write 
something like "select" and push CTRL-Space, the shown list should 
include 'ATTR_ID' and 'from', whereas ATTR_ID is the Token (Symbol) for 
an attribute at this position in the grammar. The rule looks like "query 
: "select" (ATTR_ID)? "from" OBJ_ID ("where" ...)?.

So how can I realize this?? I know I have to access  $FIRST and $FOLLOW 
respectively which is accessible in the grammar file. But I firstly need 
this information in the main java class where i create a parser object 
and my gui and secondly I do not need the BitSet (=$FIRST,$FOLLOW) but 
the names of the Tokens (Symbols), ATTR_ID f.e. When I'm right, i can 
get the last thing by matching it with the entries in the 
...TokenTypes.txt file but isn't there a better/faster way?

Thanks,
Ulrich Frank