You confusion is between '-' being part of the bareword, and - as the unary negation operator. perl -MO=Deparse,-p -e "$foo{-bar}" outputs $foo{-'bar'};. The scalar negation operator is defined rather oddly in perl -- when you try to negate a string, it doesn't nummify and then negate (which would give 0), but rather prepends a dash.

There is still some bareword magic going on, to turn the b (in your example) into 'b' rather then a call to the (non-existant) b() function.

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In reply to Re: bareword hash keys by theorbtwo
in thread bareword hash keys by John M. Dlugosz

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