>>269
ラクダ本読んでもスコープまわりの説明はいまいちハッキリしない
んだよな。perlsub(1)の「Private Variables via my()」という
見出しの中の以下の記述がオススメ。

The declared variable is not introduced (is not visible) until after
the current statement. Thus,

my $x = $x;

can be used to initialize a new $x with the value of the old $x, and
the expression

my $x = 123 and $x == 123

is false unless the old $x happened to have the value 123.