REVINPUT is the standard Toolbox data-entry routine.
All the usual editing keys are supported and entry may
be terminated by either a carriage-return or <Escape>,
in which case any keyed-in characters will be ignored.

<L.Arrow>   =  Move cursor one character to the left
<R.Arrow>   =  Move cursor one character to the right
<Home>      =  Move cursor to first character of field
<End>       =  Move cursor to last character of field
<Ctrl End>  =  Clear from current cursor position to
               the end of the entry field.
<Insert>    =  Toggle between Insert and Overtype.
<Delete>    =  Delete character under the cursor.
<BackSpace> =  Delete character under cursor and move
               the cursor one character to the left.
<F1>        =  pop up on-line HELP screen.

REVINPUT is also designed to be part of a  full-screen
data-entry system. Your program can examine the return
code  to determine whether the operator just wishes to 
terminate entry, or move forwards or backwards between
a number of entry fields.

Return Codes:   

1  =  <Escape> abort entry returning a null string
2  =  <F2>     repeat previous entry for this field
3  =  <Up Arr> pressed, move to previous field 
4  =  <Dn Arr> pressed, move to next field
5  =  <Pg Up>  pressed, move to top of screen
6  =  <Pg Dn>  pressed, move to end of screen
7  =  A hotkey was supplied and used.


An option is available to specify a string of legal
characters which REVINPUT may accept.  Any other key-
strokes will then be ignored. You can also mask off
the echo of keystrokes to the screen during password
entry routines.


See also DATEINPUT for a keyboard routine specially
designed to ask the operator for a date!!!!
