[antlr-interest] problems getting a simple grammar to accept it's input

[Florian Franzmann]

Hi,

I'm having problems getting a (so far) very simple grammar to accept it's input:

-------------------------------------

grammar Simulink;

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

INT :	'0'..'9'+
    ;

FLOAT
    :   ('0'..'9')+ '.' ('0'..'9')* EXPONENT?
    |   '.' ('0'..'9')+ EXPONENT?
    |   ('0'..'9')+ EXPONENT
    ;

COMMENT
    :   '#' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;}
    ;

WS  :   ( ' '
        | '\t'
        | '\r'
        | '\n'
        ) {$channel=HIDDEN;}
    ;

STRING
    :  '"' ( 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
    ;

fragment
BLOCK_BEGIN
	:	'{'
	;

fragment
BLOCK_END
	:	'}'
	;

file	:	block+
	;

block	:	IDENTIFIER BLOCK_BEGIN BLOCK_END
	;


-------------------------------------

This is the input:

-------------------------------------

# bla
Model {
}

-------------------------------------

And here is what happens when I try to feed it to the grammar:

-------------------------------------
$ make smalltests
antlr3 -verbose -trace -report Simulink.g
ANTLR Parser Generator  Version 3.3 Nov 30, 2010 12:50:56
Simulink.g
Simulink.file:65:8 decision 1: k=1
javac -classpath antlr/antlr-3.3-complete.jar:. SimulinkLexer.java
javac -classpath antlr/antlr-3.3-complete.jar:. SimulinkParser.java
javac -classpath antlr/antlr-3.3-complete.jar:. Test.java
cat testdata/empty.mdl                | java -classpath antlr/antlr-3.3-complete.jar:. Test
enter COMMENT # line=1:0
exit COMMENT M line=2:0
enter IDENTIFIER M line=2:0
exit IDENTIFIER   line=2:5
enter file [@1,6:10='Model',<4>,2:0]
enter block [@1,6:10='Model',<4>,2:0]
enter WS   line=2:5
exit WS { line=2:6
line 2:6 no viable alternative at character '{'
enter WS 
 line=2:7
exit WS } line=3:0
line 3:0 no viable alternative at character '}'
enter WS 
 line=3:1
exit WS 
 line=4:0
enter WS 
 line=4:0
exit WS  line=5:0
line 5:0 mismatched input '<EOF>' expecting BLOCK_BEGIN
exit block [@6,17:17='<EOF>',<-1>,5:0]
exit file [@6,17:17='<EOF>',<-1>,5:0]
-------------------------------------

As I understand it the parser consumes 'Model' as IDENTIFIER and goes into
state block. It ignores a WS, then finds a '{'. This should be recognized as
BLOCK_BEGIN, which is the next token expected in block---any idea what I'm
doing wrong?

best regards
Florian Franzmann