INPUTNULL

The INPUTNULL statement allows the definition of a character that will allow a null input to be seen by the INPUT@ statement.

COMMAND SYNTAX

    INPUTNULL expression

SYNTAX ELEMENTS

The expression should evaluate to a single character. Subsequently, any INPUT@ statement that sees only this character input before the new-line sequence will NULL the variable in which input is being stored.

If expression evaluates to the NULL string " then the default character of _ is used to define a NULL input sequence.

NOTES

The INPUT statement does not default to accepting the _ character as a NULL input, the programmer must explicitly allow this with the statement: INPUTNULL ''. In the example below an ampersand can be used to input the empty value.

EXAMPLE

    INPUTNULL "&"
    INPUT @(10,10):Answer,1
    IF Answer = '' THEN
       CRT "A NULL input was received"
    END