Function - IsDate(expression)

ISDATE - Returns the value indicating if an expression is a date (Boolean).
Validates a date using the WRS
This function should always be used before trying to convert a different data type to a date.
This function tests if a string can be evaluated as a date according to the WRS and windows language version. This function doesn't recognise days of the week.
There is no built-in function to check if a string is a US-formatted date

Function - IsDateUS (User Defined)

The built-in function IsDate validates a date using the WRS
Uses Application.Evaluate

Function - IsNumeric

ISNUMERIC - Returns the value indicating if an expression contains a number (Boolean).
This function should always be used before trying to convert a different data type to a number.
This function tests if a string can be evaluated as a number according to WRS and windows language version.
This function does not recognise the % wildcard character that represents any character.

Function - IsBoolean (User Defined)