G'day richard.sharpe,

$var ?= "something" : "something else";

I suspect something along these lines would do what you want using existing syntax:

$var = ("something else", "something")[!!$var];
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Some examples:

$ perl -E 'my $x; $x = (0,1)[!!$x]; say $x'
0

$ perl -E 'my $x = ""; $x = (0,1)[!!$x]; say $x'
0

$ perl -E 'my $x = "X"; $x = (0,1)[!!$x]; say $x'
1
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From "Re^2: RFC: "assignary" operator ?= :":

$var1 ?= die "ERROR: \$var1 already set." : $var2;

You could do something rather exotic like:

$ perl -E 'my $x = ""; $x = (42, $x && die "Set: $x")[!!$x]; say $x'
42

$ perl -E 'my $x = "X"; $x = (42, $x && die "Set: $x")[!!$x]; say $x'
Set: X at -e line 1.
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But ask yourself:

• Do you fully understand what's happening with that code?
• Will the next maintainer fully understand what's happening with that code?
• Wouldn't a simple if/else block be easier to write, read, understand and maintain?