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