ANTLR3 : MissingTokenException when using already defined token in input in place of ID -

i stumbled upon problem while writing grammar rules create table. grammar failing when column names defined tokens in grammar (can't have column name 'create' matched 'create' keyword!

simple usecase :

grammar hello;   start   :        'hello' 'world' id      ;  id : 'a'..'z'+ ; ws : (' '|'\n'|'\r')+ {$channel=hidden;} ; 

for grammar how make "hello world hello" valid input. failing missingtokenexception.

ast

                root                  |                    start     __________________________________     |              |                  |   hello          world             missingtokenexception    

thanks in advance.

edit:

i have found inline-rule while definition rule "hello" & "world", still find how works.

grammar hello;   stat: keyhello keyworld expr      ;  expr: id ;  /** id text "hello" */ keyhello : {input.lt(1).gettext().equals("hello")}? id ;  /** id text "world" */ keyworld : {input.lt(1).gettext().equals("world")}? id ;     // end:rules  id : 'a'..'z'+ ; ws : (' '|'\n'|'\r')+ {$channel=hidden;} ; 

ast

                root                  |                    start     __________________________________     |              |                  |  keyhello        keyworld             expr        |               |                  |   hello           world             world 

hope might help.

when parsing language, have "reserved words". it's impossible work without them. in case, have 2 options:

1. define group of reserved words , make id extension of it. don't recommend possibility because terrible mess when work entire grammar, or when use lexer-parser-tree, , want make different tokens or reserved words (maybe skip them).

   rw: 'hello' | 'world';  id: 'a'..'z'+ | rw; 

in case able sure when parsing rw, not id, because id , rw go through same rule...

2. choose other reserved words, better 'hello' or ordinary words it. me, best option.

taking case of second option can define 1 subgroup apart these news id's tell you. can establish difference between selected group of words vocabulary ('world','hello' etc.) , deal them different in tree.

i hope you!!