I found something interesting the other day … non-uppercase characters were testing positive for ^$IsUppercase. While you might presume only an uppercase character/string would test positive for this, it is actually testing to be sure there are no lower-case alphabetic characters. The opposite is also true with ^$IsLowercase testing for Not Uppercase. So you first need to be sure you don’t have either a number or a non-alphabetic character if that is important before using either ^$IsUppercase or ^$IsLowercase

Testing the ^$IsUppercase function:

; by don at htmlfixit.com
; any-non lowercase non-alphabetic
; character tests positive as Uppercase
^!SetArray %Original%="0";"1";"|";"?";"a";"@";"1";"+";"=";"F";"`";"~";"-";"q";"L";"[";"}";" ";"x"
^!Set %count%=0
:Loop
^!Inc %count%
^!If "^%count%" > "^%Original0%" End

^!If "^$IsUppercase("^%Original^%count%%")$" = "1" UPPER ELSE NOTUPPER

:UPPER
^!Info "^%Original^%count%%" is POSITIVE when tested as upper case -- even if it isn't a letter
^!GoTo Loop

:NOTUPPER
^!Info "^%Original^%count%%" is negative when tested as upper case
^!GoTo Loop

Testing the ^$IsLowercase function:

; by don at htmlfixit.com
; any-non lowercase non-alphabetic
; character tests positive as Uppercase
^!SetArray %Original%="0";"1";"|";"?";"a";"@";"1";"+";"=";"F";"`";"~";"-";"q";"L";"[";"}";" ";"x"
^!Set %count%=0
:Loop
^!Inc %count%
^!If "^%count%" > "^%Original0%" End

^!If "^$IsLowercase("^%Original^%count%%")$" = "1" UPPER ELSE NOTUPPER

:UPPER
^!Info "^%Original^%count%%" is POSITIVE when tested as lower case -- even if it isn't a letter
^!GoTo Loop

:NOTUPPER
^!Info "^%Original^%count%%" is negative when tested as lower case
^!GoTo Loop

I wanted to see if ^$GetLinecount$ updates on the fly every time a line is deleted. It does as shown by the following clip:

; by don at htmlfixit.com
; this clip is to show that
; if you delete lines the
; variable ^$GetLinecount$ updates
; itself on the fly

;create file
^!Menu File/New
;put 10 lines in the file
^!InsertText 1^P2^P3^P4^P5^P6^P7^P8^P9^P10
;display linecount, should be 10
^!Info Line Count: ^$GetLinecount$
;put cursor at bottom
^!Jump Doc_End
;select to line 6
^!SelectTo 6:1
;delete last 5 lines
^!Keyboard DELETE
^!Keyboard BACKSPACE
;display linecount, should be 5
^!Info Line Count: ^$GetLinecount$
; it works! ^$GetLinecount$ updates