ANTLR - parameters

I started learning ANTLR and I was looking at sample grammars. I found the CSV grammar quite interesting:

grammar CSV; 

file: hdr row+ ; 
hdr : row ; 

row : field (',' field)* '\r'? '\n' ; 

field 
    : TEXT 
    | STRING 
    | 
; 

TEXT   : ~[,\n\r"]+ ; 
STRING : '"' ('""'|~'"')* '"' ;

      

        
        
        
      

    

Is it possible to tell antlr that each line should be the same length as hdr?

In my application, I need such a mechanism. To put it simply, Id like to read in an INT variable contacting the length N of the array and after it the values ​​of N. Something like this:

// example-Input I want to parse 
A = 3 
a_0 = 2 
a_1 = 5        //there have to be exactly A = 3 a_ entries
a_2 = 3

      

        
        
        
      

    

Is this possible with antlr? And if not directly in grammar, could it be dione after something?