How do I mix ly and scheme in define-music-function

[Kevin Dalley]

I want to stick an if statement in the middle of setting many values:

This doesn't work.  The if block appears to be skipped.

By the way, in the real code, I replace #t with something else, but if
I can't get it to work with #t, there is something wrong with my
understanding.

The later block does work.

setAltStaff = #(define-music-function (parser location style lowerOctave 
upperOctave)
              (string? number? number?)
                
                (if #t
                  #{
                  \set shapeNoteStyles  = #(chromatic-value notation-style 
"shape-note-styles")
                  \set shapeLayout = #shapeSemitone
                  #})
#{
              \set Staff.clefGlyph = #"clefs.G"
              \set middleCPosition = #(chromatic-value $style "middleCPosition")
              \set clefPosition = #(+ (chromatic-value $style 
"middleCPosition") (chromatic-value $style "g-clef-from-c"))
              \set staffLineLayout = #(chromatic-value $style "layout")
              \override Staff.StaffSymbol #'line-count = #(length 
(all-lines-notation $style $lowerOctave $upperOctave))
              \override Staff.StaffSymbol #'line-positions = 
#(all-lines-notation $style $lowerOctave $upperOctave)
              \override Staff.StaffSymbol #'internal-ledger-lines = 
#(all-ledgers-notation $style $lowerOctave $upperOctave)
#}
)