Names in CLEM expressions that aren’t names of functions are assumed to be field names.

You can write these simply as Power, val27, state_flag, and so on, but if the name begins with a digit or includes non-alphabetic characters, such as spaces (with the exception of the underscore), place the name within single quotation marks (for example, 'Power Increase', '2nd answer', '#101', '$P-NextField').