@subsection Markup construction in Scheme
@cindex defining markup commands
+@funindex \displayScheme
+
+Markup expressions are internally represented in Scheme using the
+@code{markup} macro:
-The @code{markup} macro builds markup expressions in Scheme while
-providing a LilyPond-like syntax. For example,
@example
-(markup #:column (#:line (#:bold #:italic "hello" #:raise 0.4 "world")
- #:larger #:line ("foo" "bar" "baz")))
+(markup @var{expr})
+@end example
+
+To see a markup expression in its Scheme form, use the
+@code{\displayScheme} command:
+
+@example
+\displayScheme
+\markup @{
+ \column @{
+ \line @{ \bold \italic "hello" \raise #0.4 "world" @}
+ \larger \line @{ foo bar baz @}
+ @}
+@}
@end example
@noindent
-is equivalent to:
+Compiling the code above will send the following to the display
+console:
+
@example
-#@{ \markup \column @{ \line @{ \bold \italic "hello" \raise #0.4 "world" @}
- \larger \line @{ foo bar baz @} @} #@}
+(markup
+ #:line
+ (#:column
+ (#:line
+ (#:bold (#:italic "hello") #:raise 0.4 "world")
+ #:larger
+ (#:line
+ (#:simple "foo" #:simple "bar" #:simple "baz")))))
@end example
+To prevent the markup from printing on the page, use
+@w{@samp{\void \displayScheme @var{markup}}}. Also, as with the
+@code{\displayMusic} command, the output of @code{\displayScheme}
+can be saved to an external file. See
+@ref{Displaying music expressions}.
+
@noindent
This example demonstrates the main translation rules between regular
LilyPond markup syntax and Scheme markup syntax. Using @code{#@{
@item @code{\markup-command} @tab @code{#:markup-command}
@item @code{\variable} @tab @code{variable}
@item @code{\center-column @{ @dots{} @}} @tab
- @code{#:center-column ( @dots{} )}
+ @code{#:center-column ( @dots{} )}
@item @code{string} @tab @code{"string"}
@item @code{#scheme-arg} @tab @code{scheme-arg}
@end multitable
\override #'(box-padding . 0.6) \box @{ #text @}#@}))
@end lisp
-or, equivalently
+or, equivalently
@lisp
#(define-markup-command (double-box layout props text) (markup?)