Booleans

True and False, how any value becomes Boolean, and that Bool is a number.

Bool has two values, True and False. Any value can be viewed as a Boolean — its "truthiness" — and Bool is itself an Int enum, so it participates in arithmetic.

The two values #

say True;
say False;
say True.Int;

True
False
1

Truthiness — so / ? #

so (and the prefix ?) coerces any value to Bool. Zero, the empty string, and empty collections are false; almost everything else is true.

say so 5;
say so 0;
say so "";

True
False
False

Bool is a number #

True and False are the enum values 1 and 0, so they add up — handy for counting matches.

say True + True;
say (5 > 3);

2
True

Notes #

• Because Bool numifies, +@matches.grep(...) or [+] @flags counts true values directly.
• Comparison and logic operators return Bool; a bare regex match returns a truthy Match, which so/? collapse to True/False.
• The negation ! and the low-precedence not produce Bool from any value: !0 is True.