Masks and ranges can be specified for use in validating the text of entry fields. Masks limit input to a specific type of character in each position, such as numeric characters or alphabetic characters, and specify conversion of characters to uppercase or lowercase. Ranges limit values to a particular range.

ESL provides international character support for masks and ranges. A mask or a range is interpreted according to the character set being used when the program is run. The composition of the character set and the rules that order the character set are used when validating a character from the entry field.

For example, specifying:

validation is mask "DDAAXXUU" 

allows numbers in the first two places (DD), alphabetic characters in the next two places (AA), any characters in the next two places (XX), and converts characters in the last two places to uppercase (UU).

What characters meet the requirements of each placeholder in the mask is determined by what character set is in effect. For example, "a", "a", "ee", and "c'' are accepted as alphabetic characters. The order for ranges depends both on the character set and the language rules in effect.

See the entry field definition for further information on how to use masks and ranges.