antlr4 line 1:10 mismatched input when using conflicting names

Question

I am using a limit token in my sql grammar. It works fine, but when I use the column name same as the token name I get into problem. I have a column name that is also the same name as of limit. How do I solve this issue?

Output:

line 1:10 mismatched input 'limit' expecting VAL
line 1:10 mismatched input 'limit' expecting VAL

Input:

select a, limit from abc limit 55 ;

Grammar:

grammar SQLCmd;

parse : sql
;

sql : ('select' ((columns (',' columns)*)|count) 'from')
      tables
      ('where' condition ((and|or) condition)*)*  (limit)? ';'
;

num : NUM
;

count : 'count(*)'
;

columns : VAL
;

limit : 'limit' num
;

tables : VAL
;

condition : ( left '=' right )+
;

and : 'and'
;

or : 'or'
;

left : VAL
;

right : VAL
;

NUM : [0-9]+
;

VAL : [*a-z0-9A-Z~?]+
;


WS : [ \t\n\r]+ -> skip
;

Answer 1

You have to expand your columns rule to allow limit:

columns
  : VAL
  | 'limit'
  ;