Hi
Using two grammars below, ANTLR generates code that is not compilable
with either C or C++ compiler. Specifically, generated file
"ExampleGrammarEval.c" contains expression "MyStruct value = NULL;"
which is not valid C/C++ (because value is not pointer) so the code
doesn't compile. There is a work around which makes
"ExampleGrammarEval.g" bigger and harder to read. Also, this
workaround is not practical to apply for larger struct with more
member variables.
Following are the 2 grammars needed to reproduce the bug, and the
third one that describes workaround.
-------------------------------------cut
here-----------------------------------------
grammar ExampleGrammar;
options {
output=AST;
ASTLabelType=pANTLR3_BASE_TREE;
language=C;
}
tokens {
PLUS = '+';
}
prog : expr EOF!;
expr : addition;
addition : atom ( (PLUS)^ atom )*;
atom : NUMBER;
fragment DEC_DIGIT : '0'..'9' ;
NUMBER : DEC_DIGIT+;
WS : (' '|'\r'|'\t'|'\u000C'|'\n') {$channel=HIDDEN;};
-------------------------------------cut
here-----------------------------------------
-------------------------------------cut
here-----------------------------------------
tree grammar ExampleGrammarEval;
options {
tokenVocab=ExampleGrammar;
ASTLabelType=pANTLR3_BASE_TREE;
language=C;
}
@includes {
typedef struct {
double d1, d2;
} MyStruct ;
}
prog returns [MyStruct value]
: expr { $value = $expr.value; };
expr returns [MyStruct value]
: addition { $value = $addition.value; };
addition returns [MyStruct value]
: ^(PLUS a=atom b=atom) {
$value.d1 = $a.value.d1 + $b.value.d1;
$value.d2 = $a.value.d2 + $b.value.d2;
}
| atom {
$value = $atom.value;
};
atom returns [MyStruct value]
// Here is actually some parsing done to convert string into numerical
// value which is omited for simplicity.
: NUMBER { value.d1 = value.d2 = 0.0 };
-------------------------------------cut
here-----------------------------------------
-------------------------------------cut
here-----------------------------------------
tree grammar ExampleGrammarEval;
options {
tokenVocab=ExampleGrammar;
ASTLabelType=pANTLR3_BASE_TREE;
language=C;
}
@includes {
typedef struct {
double d1, d2;
} MyStruct ;
}
prog returns [double d1, double d2]
: expr { $d1 = $expr.d1; $d2 = $expr.d2; };
expr returns [double d1, double d2]
: addition { $d1 = $addition.d1; $d2 = $addition.d2; };
addition returns [double d1, double d2]
: ^(PLUS a=atom b=atom) {
$d1 = $a.d1 + $b.d1;
$d2 = $a.d2 + $b.d2;
}
| atom {
$d1 = $a.d1; $d2 = $b.d2;
};
atom returns [double d1, double d2]
// Here is actually some parsing done to convert string into numerical
// value which is omited for simplicity.
: NUMBER { value.d1 = value.d2 = 0.0 };
-------------------------------------cut
here-----------------------------------------
List: http://www.antlr.org/mailman/listinfo/antlr-interest
Unsubscribe:
http://www.antlr.org/mailman/options/antlr-interest/your-email-address
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"il-antlr-interest" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/il-antlr-interest?hl=en
-~----------~----~----~----~------~----~------~--~---
