1. Re: Input Numbers
> I find that for a project I am working on, I need some
> "bulletproof" routines for numeric input which allow for "full"
> input editing (at least supporting destructive backspace). At a
> minimum, I need to be able to optionally restrict input to
> integral values; best would be if I could both restrict the type
> (integer vs. float/atom) and the range (lowest and highest
> allowed values, allowing for open-ended ranges). I would be duly
> grateful if someone could point me in an appropriate direction.
>
> Jeff Zeitlin
> jeff.zeitlin at earth.execnet.com
Here's something that should help.
Steve Elder
--------- code begins here
include get.e
include graphics.e
global function input(sequence prompt)
-- print a message and read in a number
-- returns the number, that can either be an integer or an atom(float)
sequence input, curpos
input = {1, 0} -- this initializes the variable input with
-- values that are *not* valid
puts(1, prompt) -- put message on screen
while input[1] do -- repeat until valid number
curpos = get_position() -- read current cursor position
input = get(0) -- read from the keyboard
position(curpos[1], curpos[2]) -- back to position if not valid
end while
puts(1, '\n') -- to start on a new line when back from
function
return input[2] -- the second element of input is returned
-- and should contain a valid number
end function
-- usage:
object a -- Restricts input to integer. Otherwise declare a as an
--atom or object
a = input("enter a number: ")
-- an example of restricting input to 10 or less
if a > 10 then
puts(1,"your number must be 10 or less")
else
? a
end if
