[antlr-interest] About removing the "; " In the last sentence of a block

[roberto]

Thank you very much, is exactly what I was trying to achieve.

I did a small change to what you sent me.

Inside the "program" and "block" rule I made the ';' optional.

==========================================
program : statement_list  ';'? EOF ;
...
block : '*' '{' statement_list ';'? '}' ;
============================================

thank for your help...
Roberto

On 12/7/2011 4:38 PM, John B. Brodie wrote:
> Greetings!
>
> Replace your first 5 rules (e.g. program, statement_list, statement,
> compound_statement, and expression_statement) with these two rules:
>
> program : statement_list ';' EOF ;
>
> statement_list :
>        ( expression (';' statement_list)? )
>     |  ( ';' statement_list )
>     |  ( ( sen_for | block ) statement_list? )
>     ;
>
>
> (note please find attached the complete test grammar i used to test this...)
>
> and now that i think about it, it may not handle the last semicolon of
> the program properly when the last element of the program's
> statement_list is a block. sigh. maybe the statement_list for program
> should have the same semicolon usage as the statement_list within a
> block (e.g. the very last semicolon after the second 34 in your example
> should not be present)?
>
> anyway --- hope this helps...
>
>     -jbb
>
>
> On 12/07/2011 04:27 PM, roberto wrote:
>> Hello Everyone
>>
>> I tried to create a simple language where I want to delete the last ';' which appears in a block. Besides having compound blocks, that do not need ';' at the end of the sentence.
>>
>> This example is what I have
>>
>> *{
>>     a=34;;;;
>>     for(34)
>>     a=59;
>> }
>> a=34;
>>
>> I would like to remove the ';' which goes behind the 59. I wondered if there anyway of say when you find a TOKEN, do not consume this but continue
>>
>> expression_statement
>>        : ';'
>>        | expression (';' | *'}'*)
>>        ;
>>
>> *For example I would like that when you find the'}'generates sentence but not because it will consume the token used by the command block.
>> *
>> =============== Here is the grammar I test ====================================
>>
>> grammar lteA;
>>
>> program	
>> 	:  statement_list EOF
>> 	;
>> 	
>> statement_list
>> 	: statement+
>> 	;
>>
>> statement
>> 	: compound_statement
>> 	| expression_statement
>> 	| block
>> 	;	
>> 	
>> compound_statement
>> 	: sen_for
>> 	;
>> 	
>> expression_statement
>> 	: ';'
>> 	| expression (';' | '}')
>> 	;
>> 	
>> expression	
>> 	: ID '=' (INT | STRING | FLOAT | CHAR)
>> 	;
>> 	
>> sen_for
>> 	: 'for' '(' INT ')'
>> 	;
>> block	
>> 	: '*' '{' statement_list '}'	
>> 	;
>> 		
>> ID  :	('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')*
>>       ;
>>
>> INT
>> 	: '0'..'9'+
>> 	| '0' 'x' HEX_DIGIT+
>>       ;
>>
>> FLOAT
>>       :   ('0'..'9')+ '.' ('0'..'9')* EXPONENT?
>>       |   '.' ('0'..'9')+ EXPONENT?
>>       |   ('0'..'9')+ EXPONENT
>>       ;
>>
>> COMMENT
>>       :   '//' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;}
>>       |   '/*' ( options {greedy=false;} : . )* '*/' {$channel=HIDDEN;}
>>       ;
>>
>> WS  :   ( ' '
>>           | '\t'
>>           | '\r'
>>           | '\n'
>>           ) {$channel=HIDDEN;}
>>       ;
>>
>> STRING
>>       :  '"' ( ESC_SEQ | ~('\\'|'"') )* '"'
>>       ;
>>
>>
>> CHAR:  '\'' ( ESC_SEQ | ~('\''|'\\') ) '\''
>>       ;
>>
>> fragment
>> EXPONENT : ('e'|'E') ('+'|'-')? ('0'..'9')+ ;
>>
>> fragment
>> HEX_DIGIT : ('0'..'9'|'a'..'f'|'A'..'F') ;
>>
>> fragment
>> ESC_SEQ
>>       :   '\\' ('b'|'t'|'n'|'f'|'r'|'\"'|'\''|'\\')
>>       |   UNICODE_ESC
>>       |   OCTAL_ESC
>>       ;
>>
>> fragment
>> OCTAL_ESC
>>       :   '\\' ('0'..'3') ('0'..'7') ('0'..'7')
>>       |   '\\' ('0'..'7') ('0'..'7')
>>       |   '\\' ('0'..'7')
>>       ;
>>
>> fragment
>> UNICODE_ESC
>>       :   '\\' 'u' HEX_DIGIT HEX_DIGIT HEX_DIGIT HEX_DIGIT
>>       ;
>>
>> ===================================================================
>>    best
>> regard Roberto
>>
>>
>> Note:
>> I rewrite because was scribble when convert the HTML to text
>>
>>
>>