c# 4.0 - Access Channels in ANTLR 4 and Parse them separately -

i have included comments in separate channel in antlr 4. in case channel 2.

this lexer grammar.

comment: '/*' .*? '*/' -> channel(2)         ; 

i want access channel 2 , parse on channel accumulate comments. included in parsing grammar below

comment :comment ; 

in program

        string s = " paring string"         antlrinputstream input = new antlrinputstream(s);         csslexer lexer = new csslexer(input);           commontokenstream tokens = new commontokenstream(lexer,2); 

then want parsing on tokens

var xr = parser.comment().getrulecontexts<commentcontext>(); 

because want information commentcontext object such start.column etc.

edit:

this improved question

to more specific, want tokens in channel 2 , parse them using comment grammar comments list(ireadonly<commentcontext>) can iterate through each of these , access information such as, start line, start column, end line end column, , token text.

commontokenstream tokens = new commontokenstream(lexer,2); 

this not giving me tokens in channel 2. , thing discovered until these tokens passed arguments parser construct xparser parser = new xparser(tokens);

then can access the tokens calling gettokens().in tokes can see there comments identified tokens , in channel 2. though commenttokenstrem species channel number above. contains tokens.

1. what reason of not able access tokens until parser object created using tokens?

2. i want commenttokenstrem in channel 2 , pass xparser object creation parse these tokens using comment grammar. best way of doing in antlr 4 api?

commontokenstream internally tracks tokens channel. thing won't see when call gettokens() lexer rules -> skip action executed (no token created rules).

you can @ tokens on channel 2 using tokenstream.lt , intstream.consume methods.

java example

commontokenstream cts = new commontokenstream(tokensource, 2); list<token> tokens = new arraylist<token>(); while (cts.la(1) != eof) {     tokens.add(cts.lt(1));     cts.consume(); } 

c# example:

commontokenstream cts = new commontokenstream(tokensource, 2); ilist<itoken> tokens = new list<itoken>(); while (cts.la(1) != eof) {     tokens.add(cts.lt(1));     cts.consume(); }