Hi
I am reposting here as I did not get any feedback from the
antlr-interest. Sorry about that but I am blocked on this point.
In the following grammar, the syntactic predicates of the rule
INTERGER_OR_DECIMAL are generated in an order different from what
specified? Did I misunderstand something??
fragment
NL : ('\n'| '\r' '\n' );
fragment
ESC : '\'' '\'';
STRING : '\'' ( ESC | ~'\'' )* '\'' { };
fragment
WS : ( ' ' | '\t' | ';' | NL);
SPACE : (WS)+ {$channel=HIDDEN;};
fragment
PLUS_CHAR : '+';
fragment
MINUS_CHAR : '-';
fragment
STAR_CHAR : '*';
fragment
SLASH_CHAR : '/';
fragment
DOT_CHAR : '.';
fragment
COMMA_CHAR : ',';
fragment
PLUS : '+' WS;
fragment
MINUS : '-' WS;
fragment
STAR : '*' WS;
fragment
SLASH : '/' WS;
fragment
DOT : '.' (WS|EOF);
fragment
COMMA : ',' WS;
PLUS_OR_CHAR : ('+' WS)=> PLUS { $type=PLUS; } | PLUS_CHAR {
$type=PLUS_CHAR; };
MINUS_OR_CHAR : ('-' WS)=> MINUS { $type=MINUS; } | MINUS_CHAR {
$type=MINUS_CHAR; };
STAR_OR_CHAR : ('*' WS)=> STAR { $type=STAR; } | STAR_CHAR {
$type=STAR_CHAR; };
SLASH_OR_CHAR : ('/' WS)=> SLASH { $type=SLASH; } | SLASH_CHAR {
$type=SLASH_CHAR; };
DOT_OR_CHAR : ('.' (WS|EOF))=> DOT { $type=DOT; } | DOT_CHAR {
$type=DOT_CHAR; };
COMMA_OR_CHAR : (',' WS)=> COMMA { $type=COMMA; } | COMMA_CHAR {
$type=COMMA_CHAR; };
fragment
DIGIT : '0'..'9';
fragment
SIGN : ( PLUS_CHAR | MINUS_CHAR );
fragment
SEPARATOR : ( DOT_CHAR | COMMA_CHAR );
fragment
INTEGER : (SIGN)? (DIGIT)+;
fragment
DECIMAL : (SIGN)? (DIGIT)* SEPARATOR (DIGIT)+ ;
INTEGER_OR_DECIMAL :
( (INTEGER WS) => INTEGER { $type=INTEGER; }
| (INTEGER DOT) => INTEGER { $type=INTEGER; }
| DECIMAL { $type=DECIMAL; }
)
;
The produced Java code is:
int alt17=3;
switch ( input.LA(1) ) {
.....
case '0' case '1': case '2': case '3': case '4': case '5': case
'6': case '7': case '8': case '9':
{ int LA17_2 = input.LA(2);
if ( (LA17_2==','||LA17_2=='.'||(LA17_2>='0' && LA17_2<='9')) ) {
alt17=3;
}
else if ( (synpred7_Cobol()) ) {
alt17=1;
}
else if ( (synpred8_Cobol()) ) {
alt17=2;
}
else {
if (state.backtracking>0) {state.failed=true; return ;}
NoViableAltException nvae =
new NoViableAltException("", 17, 2, input);
throw nvae;
}
}
which does not correspond to the order of the alternatives in the the
rule INTEGER_OR_DECIMAL and resolves the input '1.;' to a DECIMAL
while it should resolve as an INTEGER since a DIGIT is followed by a DOT
and not a DOT_CHAR
My expectation would be that the order of generated code follows the
alternatives in the rule INTEGER_OR_DECIMAL as:
{
int LA17_2 = input.LA(2);
if ( (synpred7_Cobol()) ) {
alt17=1;
}
else if ( (synpred8_Cobol()) ) {
alt17=2;
} else
if ( (LA17_2==','||LA17_2=='.'||(LA17_2>='0' && LA17_2<='9')) ) {
alt17=3;
}
else {
if (state.backtracking>0) {state.failed=true; return ;}
NoViableAltException nvae =
new NoViableAltException("", 17, 2, input);
throw nvae;
}
}
which parses the input '1.;' as an INTEGER.
zos
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