19.6.2. Format masks
Format masks are defined in the
mask attribute in a cell or formula. There are two types of format masks: one for numbers, and one for dates.
19.6.2.1. Number masks
When a format mask is encountered, a check is executed to see if the mask follows an internal form, for example,
format1, accounting_float, etc. (See jxl.write.NumberFormats.)
If the mask is not part of the internal list, it is treated as a custom mask (for example,
0.00), and automatically converted to the closest match. (See java.text.DecimalFormat.)
