in reply to
Re: Surprised by Perl parse of ternary operator
in thread Surprised by Perl parse of ternary operator
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.