Get the screen to display any initial values
I've been programming on the 400 since 1988 and this one issue regarding display files continues to remain a mystery to me. Perhaps you, or one of your knowledgeable readers, can finally provide the answer. When I design/code a screen that contains numeric input/output fields, I
prefer to use a edit code or word with the field(s) so that the screen displays any initial values in a user friendly fashion. Example: With commas and zero suppression
When the user types a new value in the field the editing is lost until the screen is redisplayed. I have no problem with that. However, if the user enters a negative number into the field --using the Field key -- not only is the editing lost, but a non-numeric character appears in the field in place of the "negative" sign that remains there until the screen is refreshed/rewritten. This is very confusing to the user.
The best I can ever say to the user is, "Don't use the Field key, and instead place a dash after the keyed numeric value". Surely there must be a better solution than this?
The simple answer is "smoke and mirrors." The keyboard shift"N" in DDS will allow it to be displayed as a minus sign. If you add an edit code, it will not compile, as that keyboard shift will not allow any editing. The best answer is to remap the user's Field Minus key to a real minus key, and leave the shift-field exit set to Field Minus. Most emulators will automatically convert the field.
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This was first published in June 2002