CODEWITHSUNDEEP
antlrgrammarantlrworks
Andrey Agibalov
Andrey Agibalov

Reputation: 7694

Making ANTLRWorks handle whitespaces automatically

I have an ANTLR grammar like this:

grammar HelloGrammar1;

ID  :   ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')* ;
STATEMENT : 'hello' ID ';' ;
WS  :   (' '|'\t'|'\r'|'\n')* ;

I want it to parse the following text: hello qwerty ;. It doesn work this way. If I change my string to helloqwerty;, everything is fine. I can also change grammar to:

grammar HelloGrammar2;

ID  :   ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')* ;
STATEMENT : 'hello' WS ID WS ';' ;
WS  :   (' '|'\t'|'\r'|'\n')* ;

And in this case, hello qwerty ; works fine. Is it possible to make ANTLR skip whitespaces automatically? (i.e. - I want to make HelloGrammar1 work with hello qwerty ;)

Update

If it makes sense: I'm testing it in ANTLRWorks.

Update 2

Also tried this way:

grammar HelloGrammar;

ID  :   ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')* ;
STATEMENT : 'hello' ID ';' ;
WS  :   (' '|'\t'|'\r'|'\n') { $channel = HIDDEN; } ;

Still doesn't work.

Update 3

I'm using "Interpreter" tab with "STATEMENT" rule selected.

Upvotes: 1

Views: 212

Answers (1)

luketorjussen
luketorjussen

Reputation: 3264

I think the issue may be that you should change STATEMENT (currently a lexer rule) to statement (a parser rule)

grammar HelloGrammar;

statement : 'hello' ID ';' ;
ID  :   ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')* ;
WS  :   (' '|'\t'|'\r'|'\n') { $channel = HIDDEN; } ;

In ANTLRWorks this accepts:

hello qwerty;
hello   qwerty;
hello loki2302;
hello   qwerty  ;

but does not accept:

helloqwerty;
helloqwerty ;
hello;
hello qwerty

Upvotes: 2

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