Rick et al:

Following up on J Law's recent question, I too have noticed that users are surprisingly daunted by the logical functions in 3dcalc.

In the interests of bringing the great 3dcalc functionality to the largest possible audience, with almost no additional investment, I'd like to propose that at some point the following functions be introduced:

-- notzero() as a synonym for bool()

-- iszero() as a clearer shorthand for the idiom (1-bool())

-- equals(arg1, arg2) as a clearer shorthand for (1-bool(arg1-arg2)).

This would make some oft-used mask manipulation formulae very easy to understand and use.

(I think "step" could benefit from a similar friendlification along the same lines.)

Graham