Scheme help request: How can else of an if-statement be made to do nothing?

[Matthew Fong]

Hello everyone,

I've been digging into guile/scheme and LilyPond, and it doesn't appear
that else-statements can be empty. Any pointers would be appreciated in
advance.

For the example below, I would prefer the else-statement here to do
nothing, rather than print an empty markup: \markup { "" }, as doing so
creates a small, but observable change in vertical spacing.

% Print markup if a symbol is defined
#(define-markup-command (PrintIfDefined layout props sym text) (symbol?
markup?)
    (if (defined? sym)
        ;; Do this if true
        (interpret-markup layout props
            #{ \markup \with-color #'(0.8 0.2 0.2) #text #})
   ;; How do I do nothing here? (empty statement preferred)
   (interpret-markup layout props
       #{ \markup "" #})
)
)

printInfo = 1
\markup \PrintIfDefined #'printInfo "Print this if symbol printInfo is
defined"


Many thanks,
mattfong