GET-grammar rule - please help for understanding

[silvia.iva...@gmail.com]

Hello, I have a antlr v4-grammar and I am trying to understand the GET-rule of this grammar, but I do not understand where I am wrong.I think I must use JSON instead of MAP but when I use JSON the program throws too many exceptions. 

Could you please help me? 

Here is the program, that I have generated.

PROGRAM aa{
MAP m;
m = '{"aaaa":"17"}' ;
PRINT GET (m , "aaaa")  ;
}

Here is the grammar for the language above.

grammar program;
prule: PROGRAM VARIABLE block;


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


NUMBER: '-'? '0'..'9'+([.,]'0'..'9'+)?;
TEXT: '"' .* '"';
JSON: '\'' .* '\'';
OPEN_BLOCK: '{';
CLOSE_BLOCK: '}';
ASSIGNMENT: '=';
MAPDECL: 'MAP';
DOUBLEDECL: 'DOUBLE';
TEXTDECL: 'TEXT';
BOOLDECL: 'BOOLEAN';
PRINT: 'PRINT';
OPEN_BRACKET: '(';
CLOSE_BRACKET: ')';
COMMA: ',';
PROGRAM: 'PROGRAM';
SMALLER: '<';
GREATER: '>';
TRUE: 'TRUE';
FALSE: 'FALSE';
GET: 'GET';
SEMICOLON: ';';
VARIABLE: ('a'..'z'|'A'..'Z')+;


block: OPEN_BLOCK statement+ CLOSE_BLOCK;


statement: (assignment |
            mapdecl |
            booldecl |
            doubledecl |
            textdecl |
            print
           ) SEMICOLON;


mapdecl: MAPDECL VARIABLE;
booldecl: BOOLDECL VARIABLE;
doubledecl: DOUBLEDECL VARIABLE;
textdecl: TEXTDECL VARIABLE;


print: PRINT (expression | logexpression);


assignment: VARIABLE ASSIGNMENT (expression | logexpression);


expression: factor ((OPERATOR_ADD|OPERATOR_SUB) expression)?;


factor: (NUMBER |
         TEXT |
         TRUE |
         FALSE |
         JSON |
         get |
         VARIABLE (OPEN_BRACKET (expression (COMMA expression)*)? CLOSE_BRACKET)? |
         OPEN_BRACKET op=expression CLOSE_BRACKET)
        ((OPERATOR_MULT | OPERATOR_DIV) factor)?;


get: GET OPEN_BRACKET expression COMMA TEXT CLOSE_BRACKET;

[Geoff Groos]

I'm having trouble understanding your question.

I think I must use JSON instead of MAP

so you would like to write and parse the program

PROGRAM aa{
PRINT GET ('{"aaaa":"17"}' , "aaaa")  ;
}


Is that it?

You're current parsing system will parse this, so if you're encountering exceptions it would be from the implementation of the visit-listeners. Have you tried putting a breakpoint there to see if you can figure out whats going on?

I suggest you follow the standard SSCCE approach to this problem, with something like

"using this grammar, to parse this program, I expect to get X but infact I get Y"

Then I will understand your problem much better.

Cheers!