Can't parse an existing expression with the antlr4 grammar(see it in the question)

Question

I have the following grammar

grammar ExpressionsParserGrammar;

expression
:
    left = expression identity_operation =
    (
        IDENTITY
        | NOT_IDENTITY
    ) right = expression # identity_operation
    | left = expression equality_operation =
    (
        EQUALS
        | NOT_EQUALS
        | MORE_THAN
        | LESS
        | MORE_OR_EQUALS
        | LESS_OR_EQUALS
    ) right = expression # equality_operation
    | condition = expression '?' left = expression COLON right = expression #
    question_expr
    | left = expression mul_or_div =
    (
        MUL
        | DIV
    ) right = expression # mul_div_expr
    | left = expression plus_minus =
    (
        PLUS
        | MINUS
    ) right = expression # add_expr
    | NOT expr = expression # not_expr
    | left = expression AND right = expression # and_expr
    | left = expression OR right = expression # or_expr
    | LPAREN expr = expression RPAREN # brackets_expr
    | POWER_FUNC LPAREN expr1 = expression COMMA expr2 = expression RPAREN #
    power_expr
    | LAST_VAL_FUNC LPAREN last_str_func = STRING_VALUE
    (
        (
            COMMA config = STRING_VALUE
        )?
    ) RPAREN # last_val_func
    | LAST_STR_FUNC LPAREN last_str_func = STRING_VALUE RPAREN # last_str_func
    | SUBMISSION_VAL_FUNC LPAREN sumission_val_str = STRING_VALUE RPAREN #
    submission_val_func
    | SUBMISSION_STR_FUNC LPAREN submission_str = STRING_VALUE RPAREN #
    submission_str_func
    | DATE_FORMAT_FUNC LPAREN date_format_expr = expression COMMA formatParam =
    STRING_VALUE RPAREN # date_format_func
    | NEW DATE LPAREN
    (
        (
            expr = expression
            (
                COMMA expr = expression
            )*
        )
    )* RPAREN # date
    | DIFFERENCE_IN_HOURS LPAREN left = expression COMMA right = expression #
    dif_in_hours
    | DIFFERENCE_IN_DAYS LPAREN left = expression COMMA right = expression #
    dif_in_days
    | DIFFERENCE_IN_MINUTES LPAREN left = expression COMMA right = expression #
    dif_in_minutes
    | DATE_ADD LPAREN date = expression COMMA d=duration RPAREN  # dateAddFunc
    | DATE_SUBTRACT LPAREN date = expression COMMA d=duration RPAREN  # dateSubtractFunc
    | NOW LPAREN RPAREN # now
    | numLiteral = NUMBER_LITERAL # process_number
    | strValueLiteral = STRING_VALUE # process_str
    | boolLiteral =
    (
        TRUE
        | FALSE
    ) # process_bool
;

duration:L_CURLY_BRACE (YEARS COLON years =
    expression) ( COMMA MONTHS COLON months = expression)? (COMMA WEEKS COLON weeks =
    expression )? (COMMA DAYS COLON days = expression )? ( COMMA HOURS COLON hours = expression )?
    ( COMMA MINUTES COLON minutes = expression )? (COMMA SECONDS COLON seconds = expression)? R_CURLY_BRACE;
    
SECONDS: 'seconds';

MINUTES: 'minutes' ;


HOURS
:'hours'
;

DAYS
:
    'days'
;

WEEKS
:
    'weeks'
;

MONTHS
:
    'months'
;

YEARS
:
    'years'
;

OR
:
    '||'
;


AND
:
    '&&'
;

NOT
:
    '!'
;

DIFFERENCE_IN_MINUTES
:
    'differenceInMinutes'
;

DIFFERENCE_IN_DAYS
:
    'differenceInDays'
;

DIFFERENCE_IN_HOURS
:
    'differenceInHours'
;

DATE_ADD
:
    'dateAdd'
;

DATE_SUBTRACT
:
    'dateSubtract'
;


// ----------------- lexer -----------------
// using the NA pattern marks this Token class as 'irrelevant' for the Lexer.
// AdditionOperator defines a Tokens hierarchy but only the leafs in this hierarchy define
// actual Tokens that can appear in the text

COLON
:
    ':'
;

NOW
:
    'now'
;

NEW
:
    'new'
;

DATE
:
    'Date'
;

PLUS
:
    '+'
;

MINUS
:
    '-'
;

MUL
:
    '*'
;

DIV
:
    '/'
;

LPAREN
:
    '('
;

RPAREN
:
    ')'
;

NUMBER_LITERAL
:
    '0'
    |
    (
        [1-9]
        (
            [0-9]*
        )
    )
;

IDENTITY
:
    '==='
;

NOT_IDENTITY
:
    '!=='
;

EQUALS
:
    '=='
;

NOT_EQUALS
:
    '!='
;

MORE_THAN
:
    '>'
;

LESS
:
    '<'
;

MORE_OR_EQUALS
:
    '>='
;

LESS_OR_EQUALS
:
    '<='
;

LAST_VAL_FUNC
:
    'lastVal'
;

LAST_STR_FUNC
:
    'lastStr'
;

SUBMISSION_VAL_FUNC
:
    'submissionVal'
;

SUBMISSION_STR_FUNC
:
    'submissionStr'
;

POWER_FUNC
:
    'power'
;

DATE_FORMAT_FUNC
:
    'dateFormat'
;

COMMA
:
    ','
;

L_CURLY_BRACE
:
    '{'
;

R_CURLY_BRACE
:
    '}'
;

TRUE
:
    'true'
;

FALSE
:
    'false'
;

STRING_VALUE
:
    '"'
    (
        '\\"'
        | .
    )*? '"'
;

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

And on the expression

differenceInDays(new Date(1999, 10,1), true ? new Date(1999, 10,2) : "A")>3

I have following error

ExpressionsParserGrammar::expression:1:72: extraneous input ')' expecting {, '?', '||', '&&', '+', '-', '*', '/', '===', '!==', '==', '!=', '>', '<', '>=', '<='}

There is a Eclipse view of the syntax tree of my expression

Where I'm wrong and how to fix my grammar to make the mentioned expression fit to the grammar?

Answer 1

The error message "extraneous input ')' expecting {, '?', '||', '&&', '+', '-', '*', '/', '===', '!==', '==', '!=', '>', '<', '>=', '<='}" is telling you that a ) is encountered, but is unexpected. The parser is trying to continue matching an expression, which might continue if one of the tokens {, '?', '||', '&&', '+', '-', '*', '/', '===', '!==', '==', '!=', '>', '<', '>=', '<='} was found instead of ).

The root cause is that in your #dif_in_days alternative, there is no RPAREN token defined:

Instead of:

| DIFFERENCE_IN_DAYS LPAREN left = expression COMMA right = expression #dif_in_days

do this:

| DIFFERENCE_IN_DAYS LPAREN left = expression COMMA right = expression RPAREN #dif_in_days

Note that the same goes for the alternatives #dif_in_hours and #dif_in_minutes: those too are missing an RPAREN token.