In the PROMOTIC system it is better to use the Pm.StringSub method.
s = Mid(string, start[, length])
|string||(String) Text string from which characters are returned. If string contains Null, then Null is returned.|
|start||(Integer) Character position in string at which the part to be taken begins. If it is greater than the number of characters in string, then the function returns a empty string (""). The first character has the position 1.|
|length||[optional] (Integer) The number of characters to return. If omitted or if there are fewer than length characters in the text (including the character at start position), then all characters from the start position to the end of the string are returned.|
s = Mid("VB Script is fun!", 4, 6) 's contains "Script"