Re^2: CarTalk Puzzler

[Aristotle]

print sqrt==int(sqrt)?1:0for 1..2e4;

:-)

You got away with it because perl is looking for an expression; when the thing it then sees starts with a digit, it can't be anything but a literal number. So the parser eats as many characters as can be part of a literal number and then stops. For some fun, insert an x right after the 0 and watch what happens; or try any number of underscores.

[Perl Mouse]

Adding underscore doesn't add much fun. Adding an 'x' does:

$ perl -le 'print 0for 1, 2, 3'
0
0
0
$ perl -le 'print 0_for 1, 2, 3'
0
0
0
$ perl -le 'print 0xfor 1, 2, 3'
15

[Aristotle]

True; the underscore is only interesting after trying x, and mostly for looking at the B::Deparse output.