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Re^2: Need clean code

by eyepopslikeamosquito (Archbishop)
on Mar 25, 2017 at 23:17 UTC ( [id://1185963]=note: print w/replies, xml ) Need Help??


in reply to Re: Need clean code
in thread Need clean code

For what it's worth, some of this applies equally in many languages such as C and C++. There's not really a concept of definedness in C/C++, but the concept of short circuiting in expressions using ||, and of ternary operators is nearly identical.
But please be warned that the semantics of the || and && operators in C/C++ is significantly different to Perl. For example, this Perl code:

my $var; $var = 0; $var = $var || 30; print "1. var=$var\n"; $var = 0; $var ||= 30; print "2. var=$var\n";
prints:
1. var=30 2. var=30

While this C++ code:

int var = 0; var = var || 30; printf("1. var=%d\n", var); // var ||= 30; // oops, syntax error in C++
prints:
1. var=1
Why? Because in C/C++, the (short-circuiting) || and && operators always return 0 or 1. Unlike Perl, they do NOT return the last value evaluated.

IMHO, this deliberate Perl change in semantics of these two venerable short-circuiting operators was a clever innovation from Larry, making them more convenient to use, notably when setting default values.

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