我有以下代码:
# List of tests
my $tests = [("system_test_builtins_sin", "system_test_builtins_cos", "system_test_builtins_tan")];
# Provide overrides for certain variables that may be needed because of special cases
# For example, cos must be executed 100 times and sin only 5 times.
my %testOverrides = (
system_test_builtins_sin => {
reps => 5,
},
system_test_builtins_cos => {
reps => 100,
},
);
my %testDefaults = (
system_test_reps => 10,
);
# Execute a system tests
foreach my $testName (@$tests)
{
print "Executing $testName\n";
my $reps;
if (exists $testOverrides{$testName}{reps})
{ $reps = $testOverrides{$testName}{reps}; }
else
{ $reps = $testDefaults{system_test_reps}; }
print "After long if: $reps\n";
exists $testOverrides{$testName}{reps} ? $reps = $testOverrides{$testName}{reps} : $reps = $testDefaults{system_test_reps};
print "After first ternary: $reps\n";
exists $testOverrides{$testName}{reps} ? $reps = $testOverrides{$testName}{reps} : print "Override not found.\n";
print "After second ternary: $reps\n";
}
这给出了以下输出:
Executing system_test_builtins_sin
After long if: 5
After first ternary: 10
After second ternary: 5
Executing system_test_builtins_cos
After long if: 100
After first ternary: 10
After second ternary: 100
Executing system_test_builtins_tan
After long if: 10
After first ternary: 10
Override not found.
After second ternary: 10
这个输出是最出乎意料的!我不明白为什么第一个三元似乎总是在执行“if false”子句。它总是赋值10。我也尝试将“false”子句更改为$reps = 6
,我看到它总是得到6的值。为什么三元的逻辑取决于第三个(如果为假)子句的内容?