Wrong precedences for sizeof and conditional operator #51
Description
The parse trees for certain expressions involving sizeof <expr> and the ternary conditional operator are wrong. Consider the following examples:
For sizeof, this...
void f(void) {
int a;
a = sizeof a + 1;
}
...is parsed as...
[...]
(assignment_expression [2, 4] - [2, 20]
left: (identifier [2, 4] - [2, 5])
right: (sizeof_expression [2, 8] - [2, 20]
value: (binary_expression [2, 15] - [2, 20]
left: (identifier [2, 15] - [2, 16])
right: (number_literal [2, 19] - [2, 20]))))))))
...whereas this would be expected:
[...]
(assignment_expression [2, 4] - [2, 20]
left: (identifier [2, 4] - [2, 5])
right: (binary_expression [2, 8] - [2, 20]
left: (sizeof_expression [2, 8] - [2, 16]
value: (identifier [2, 15] - [2, 16]))
right: (number_literal [2, 19] - [2, 20])))))))
And for the ternary operator, this...
void f(void) {
int a;
a = 0 ? 1 : 2;
}
...is parsed as...
[...]
(conditional_expression [2, 4] - [2, 17]
condition: (assignment_expression [2, 4] - [2, 9]
left: (identifier [2, 4] - [2, 5])
right: (number_literal [2, 8] - [2, 9]))
consequence: (number_literal [2, 12] - [2, 13])
alternative: (number_literal [2, 16] - [2, 17]))))))
...whereas this would be expected:
[...]
(assignment_expression [2, 4] - [2, 17]
left: (identifier [2, 4] - [2, 5])
right: (conditional_expression [2, 8] - [2, 17]
condition: (number_literal [2, 8] - [2, 9])
consequence: (number_literal [2, 12] - [2, 13])
alternative: (number_literal [2, 16] - [2, 17])))))))
I would suggest changing the precedences in grammar.js to the following:
const PREC = {
PAREN_DECLARATOR: -10,
ASSIGNMENT: -2, // from -1
CONDITIONAL: -1, // from -2
DEFAULT: 0,
LOGICAL_OR: 1,
LOGICAL_AND: 2,
INCLUSIVE_OR: 3,
EXCLUSIVE_OR: 4,
BITWISE_AND: 5,
EQUAL: 6,
RELATIONAL: 7,
SHIFT: 8, // from 9
ADD: 9, // from 10
MULTIPLY: 10, // from 11
CAST: 11, // from 12
SIZEOF: 12, // from 8
UNARY: 13,
CALL: 14,
FIELD: 15,
SUBSCRIPT: 16
};
Edit: Apparently my suggested fix breaks other examples, e.g.
char f(int);
int main(void) {
return sizeof(f)(42);
}
(which seems odd to me since the relation between the precedence of SIZEOF and CALL is not changed by the fix.)