Verifying Numeric Input

Ken Ray kray at
Sun Aug 17 13:58:43 EDT 2008

> * Thousand separators, if allowed
> * Users whose number formats use "." as a thousands separator and "'"
> as the decimal separator.
> * Entry of multiple "."s in one number
> * Negative numbers, if allowed.  And if allowed, multiple "-"s or
> embedded "-"s.
> * Currency symbol, if allowed; And if allowed, multiple or embedded
> currency symbols.

A lot of this IMHO has to do with what might be "input filters" related to
what is desired in a given field. So I guess what's needed is along the
lines of what Excel provides for the "cell format" on a field - numeric,
accounting, currency, etc., each of which provides it's own set of accepted
input chars.
But there's also a distinction between what is allowed for *entry* vs. what
is displayed in a field. For example, I might have a currency field that
would accept separators and one decimal, but not allow currency *symbols* to
be entered (preferring to handle that in another way). So someone might
enter "4000" and I would display it as "4,000.00", or they could enter
"4,000.00" and not get an error, or they could enter "4,000.005" and either
get an error or have it round.

It sounds to me like rather than trying to provide a "does it all" handler,
that instead what needs to be defined is the different input/display
properties of a field, and then have the handler that watches for input make
sure it conforms to the input criteria and displays it using the display

BTW, Rob - just curious, but when would you see allowing multiple "-"s or
multiple currency symbols?

Ken Ray
Sons of Thunder Software, Inc.
Email: kray at
Web Site:

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