Curiously, both Ruby and PHP, both with the same relative precedence as Perl for the ternary and assignment operators, bend the rules differently. For example, this Ruby program:
config = ''
fred = 42
fred == 42 ? config = 'k1' : config = 'k2'
and PHP program:
$config = '';
$fred = 42;
$fred == 42 ? $config = 'k1' : $config = 'k2';
both run without error, but, unlike Perl (which produces config=k2
), both Ruby and PHP produce config=k1
Arguably, all three languages should produce a syntax error.
Update: gcc produces a syntax error "f.c:6: error: lvalue required as left operand of assignment" with this test program (further update: g++ compiles it happily though and with the same semantics as the Ruby and PHP test programs):
int config = 0;
int fred = 42;
fred == 42 ? config = 1 : config = 2;
Adding parentheses to line 6:
fred == 42 ? (config = 1) : (config = 2); // this works
fred == 42 ? config = 1 : (config = 2); // also works
fred == 42 ? (config = 1) : config = 2; // syntax error
makes it work the same as the Ruby and PHP test programs.