BACKSLASHEDP char
BACKSLASHED? char

	outputs TRUE if the input character was originally entered into Logo
	with a backslash (\) before it or within vertical bars (|) to prevent
	its usual special syntactic meaning, FALSE otherwise.  (Outputs TRUE
	only if the character is a backslashed space, tab, newline, or one of
	()[]+-*/=<>":;\~?| )