I agree that it's rather confusing at first but easy (and flexible) once you get the hang of it. Yes, the "% " combo does force an expression but only for that "comma section" of the command you're using. In other words,
each "comma section" of a command is separate from the others. Example:
FileSelectFile, _SourceFileName, 3, % _InputDirectory, "Select the file to be converted.", "Adobe PDF (*.pdf)"
; ^
; | ^----------------^
; | | Third "comma section" of the command. Since we want to use the contents of
; | | a variable, we can use either method, "% _InputDirectory" or %_InputDirectory%
; |
; | ^^
; | | Second "comma section" of the command.
; |
; |^--------------^
; | | First "comma section" of the command. No % used since we're declaring a variable name to store the outputted value.
; |
; |
; | Note that comma I put in. It doesn't NEED to be there but it's a good habit to get into.
Clear as mud now?
