antlr - Retrive token list from ParserRuleContext -

main question

is there easy way list of tokens (ideally in form of tokenstream) parser rule class parserrulecontext?

related answers

in answer question traversal of tokens using parserrulecontext in listener - antlr4 solution appeared:

parserrulecontext pctx = ctx.getparent(); list<terminalnode> nodes = pctx.gettokens(pctx.getstart(), pctx.getstop()); 

but there no method signature parserrulecontext::gettokens(token, token) in antlrv4.

my solution

i thought retriving list of tokens tokenstream using tokenstream:get(index: int) method, index value set range of indicies of given parserrulecontext start/stop tokens.

additional question

is there way subset of tokens tokenstream in form of tokenstream?

so, overlooked classes , inferfaces in antlrv4 api.

answer main question

proposed above solution correct. bufferedtokenstream , commontokenstream classes have method public list<token> gettokens(int start, int stop) allows retrive list of tokens given range (especially range between start token , stop token of parserrulecontext class)

answer additional question

you can utilize listtokensource class implements tokensource interface. can create commontokenstream class passing listtokensource.

code example of parserrulerewriter

i encapsulate above ideas small code example featuring parserrulerewriter - tokenstreamrewriter rewrites given parser rule. in code tokenstream parameter token stream of full program.

import org.antlr.v4.runtime.*; import java.util.list;  public class parserrulerewriter {     private tokenstreamrewriter rewriter;      public parserrulerewriter(parserrulecontext parserrule, commontokenstream tokenstream) {         token start = parserrule.getstart();         token stop = parserrule.getstop();         list<token> ruletokens = tokenstream.gettokens(start.gettokenindex(), stop.gettokenindex());         listtokensource tokensource = new listtokensource(ruletokens);         commontokenstream commontokenstream = new commontokenstream(tokensource);         commontokenstream.fill();         rewriter = new tokenstreamrewriter(commontokenstream);     }      public void replace(token token, parserrulecontext rule) {         rewriter.replace(token, rule.gettext());     }      @override     public string tostring() {         return rewriter.gettext();     } }