Like everyone else, I doubt that there is any speed saving. do() is like scalar eval `cat filename` according to perldoc and this leads me to believe that, while compile time may be quicker, runtime will actually be slower due to the overheads needed to set up the sub call. However, there are some obscure advantages to this method; I wrote a program a little while ago that called blocks of perl code from a database upon demand and eval'd them. This was slow and hard to debug but allowed large parts of the program to be edited at runtime.

$japh->{'Caillte'} = $me;