RevMedia

When we mentioned in the recent Window Common series that WC_WC% (the exit key from SCRIBE) could be used to good effect in spreadsheet emulation, regular subscribers would immediately have deduced that this subject had already reared its ugly head in Sprezzatura's day to day consultancy work (a surprisingly large number of our articles start off life that way.) In fact, this problem has been with us almost since the dawn of ARev, when one of the very few features of Revelation G which was immediately missed was the ability to define a multivalued column as both horizontal and vertical simultaneously, effectively creating a small table. This is no different in appearance from an associated multivalued group, but we all know how nasty and slow these can be to navigate around, especially when they are large.

We've mentioned before that AMV groups have their flaws in terms of database design anyway, but even among those of a strictly relational bent they are still often used as a simple collection device for a more normalised structure which is hidden from the user (this was the subject of an interesting talk by Maurice Champagne and David Wolff at the recent conference in New Orleans.) To be effective in any circumstances, however, the entry area should be easily navigable, and it should be able to cope quickly and efficiently with large arrays of data, not a currently recognised ARev feature!

One solution is to hardcode the entire spreadsheet interface yourself in R/Basic. (I've seen it done, but it's very time-consuming.) It is usually preferable to take advantage of the consistent interface, numerous processing hooks, and standard features of ARev windows. This allows the same sort of interface to be created much more quickly, and more flexibly as well.

Obviously, no single solution will fool all of the people all of the time, so we now present a series of techniques which can be adapted to your own particular circumstances. The techniques (if not the syntax) should be equally valid in all versions of ARev, although the availability of the mouse in version 3.x can help out greatly with the navigation problem. In the code segments which follow, it is assumed that Window_Common% & Edit.Keys have been made available when required. Furthermore, in these examples it is assumed that the entry area is located in a collector window which has no columns present other than those in the spreadsheet grid. It is a simple matter to adjust the code for windows which are bound to a table or which contain other prompts as well.

Recognising the problems inherent in multivalued groups, a good starting point is simply to do away with them altogether, mimicking their appearance by creating a grid of single valued prompts. This makes navigation by mouse much more straightforward; simply click on any visible cell (even in V3, the mouse is still limited to horizontal movement through AMV groups). It is a good idea to adjust the normal function of certain keystrokes as well. I prefer to use the left and right arrows exclusively for navigation between cells (consistent with the behaviour of the up and down keys - see later), rather than for movement within any given prompt. This can be achieved by means of a setup commuter call which adjusts the exit keys recognised by SCRIBE, as follows: