Stupid beginners question

[Jochen Wiedmann]

Hi,

I'd like to parse some fairly simple string, basically an ORDER BY clause. However, when I parse the input string "ORDER BY id ASC, name DESC", I get these error messages/warnings:

line 1:6 extraneous input 'BY' expecting {'AS', WS}

line 1:9 extraneous input 'id' expecting {'AS', WS}

line 1:12 extraneous input 'ASC' expecting {'AS', WS}

line 1:16 extraneous input ' ' expecting ID

line 1:22 extraneous input 'DESC' expecting {'AS', WS}

My grammar (AntLR 4) is below. Glad about any response.

Thanks,

Jochen

grammar OrderBy;

orderType

    : ( DESCENDING | ASCENDING | DESC | ASC )?

    ;

orderBy

    :  ( ORDER WS+ BY)? propertyReference (typeCast)? orderType?

                  (COMMA propertyReference (typeCast)? orderType?)*

    ;

typeCast

     : WS+ 'AS' ID

     ;

propertyReference

     : ID (DOT ID)*

     ;

ID

     : ('a'..'z' | 'A'..'Z' | '_') ('a'..'z' | 'A'..'Z' | '_' | '0'..'9')*

     ;

WS: [ \n\t\r];

ORDER

: 'ORDER'

;

BY

: 'BY'

;

DESCENDING

: 'DESCENDING'

;

ASCENDING

: 'ASCENDING'

;

DESC

: 'DESC'

;

ASC

: 'ASC'

;

COMMA

: ','

;

DOT

: '.'

;

[floor....@aimms.com]

Hi Jochen, 

The ID rule can match all your keywords, and will, because if more than one lexer rule applies, the one listed first gets picked. So move your ID rule down ( at least beneath all the keyword rules).

Regards, 

Floor

[Jochen Wiedmann]

Hi, Floor,

thanks very much for your suggestion. I did that, but now I am getting

line 1:8 extraneous input ' ' expecting ID

line 1:12 extraneous input 'ASC' expecting {'AS', WS}

line 1:16 extraneous input ' ' expecting ID

line 1:22 extraneous input 'DESC' expecting {'AS', WS}

Thanks,

Jochen

[floor....@aimms.com]

Hi Jochen, 

You probably want to add "-> skip" to your  WS rule, so you do not have to worry about whitespace in your parser rules. 

You can then remove all references to WS in your parser. 

[Jochen Wiedmann]

Thanks very much! That did the trick.