On Tue, 30 Sep 2008, Patrick R. Michaud wrote: > Just for pedantic clarity, what C< $directive ne 'VAR' & 'LOOP' & 'IF' > > really gives is > > all( $directive ne 'VAR', $directive ne 'LOOP', $directive ne 'IF' ) > > In other words, the result of the expression is an all() Junction. In > boolean context this would indeed evaluate to false if $directive has any > of the values 'VAR', 'LOOP', or 'IF'.
Does it have to be this way? In formal logic, distributing a negation over a disjunction products a conjunction and vice versa. Perl has a long tradition of dwimmery, so why are we taking a literal "distribute all symbols the same way" approach? Surely it is more important that ($a ne $b) should be equivalent to not( $a eq $b ) regardless of whether either variable contains a junction? As a start, perhaps we should be marking certain operators (not ! none() != ne) with whether they represent a logical inversion, so that conjunctions and disjunctions can be alternated? -Martin Kealey
