> We should be able to express "untrusted input" This is not even a new idea. Perl has had 'Taint' mode for a very long time, and the mode does exactly this,

> We should be able to express "untrusted input" This is not even a new idea. Perl has had 'Taint' mode for a very long time, and the mode does exactly this, labels externally supplied data as "tainted" until you "cleanse" it within your code. Naturally the level of security is dependent upon how well you write your "cleanse" routines, but the mode does prevent accidental use of untrusted input. See at least: http://perlmeme.org/howtos/secure_code/taint.html http://perlmeme.org/howtos/secure_code/taint.html