...

...

...

def ifthen(p,q): return (not p) or q

i.e. (~p | q) <-> (p -> q)

...

...

...

combos = ((True,True),(True,False),(False,True),(False,False))

...

...

...

for p,q in combos: print "Inputs: %s\t%s\tOutput: %s" % (p, q, ifthen(p,q) )

Inputs: True True Output: True Inputs: True False Output: False Inputs: False True Output: True Inputs: False False Output: True

Kirby

On more quickie regarding 'functions': I've got these integrated into a curriculum outline here: http://www.4dsolutions.net/ocn/mainoutline.html You'll see it's pretty traditional, but the context is clearly influenced by computer science. I haven't touched this document since Oct 9, 2003 but still consider it current enough to be useful in the field. Kirby