X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=Documentation%2Fextending%2Fscheme-tutorial.itely;h=7503306b1fa56f3e8c16b0f6d25b5f5e8d8f28a6;hb=058370efc7e9710f149d0f444328bb1fcd7bdec1;hp=bad8d261b214cd4e6fc1aff56dafbed1af3b6938;hpb=e6e64de1da49ff8c6005daa5fd81adc8387b2668;p=lilypond.git

diff --git a/Documentation/extending/scheme-tutorial.itely b/Documentation/extending/scheme-tutorial.itely
index bad8d261b2..7503306b1f 100644
--- a/Documentation/extending/scheme-tutorial.itely
+++ b/Documentation/extending/scheme-tutorial.itely
@@ -1134,23 +1134,30 @@ will display
 
 By default, LilyPond will print these messages to the console along
 with all the other messages.  To split up these messages and save
-the results of @code{\display@{STUFF@}}, redirect the output to
-a file.
+the results of @code{\display@{STUFF@}}, you can specify an optional
+output port to use:
 
 @example
-lilypond file.ly >display.txt
+@{
+  \displayMusic #(open-output-file "display.txt") @{ c'4\f @}
+@}
 @end example
 
-With a combined bit of Lilypond and Scheme magic, you can actually
-let Lilypond direct just this output to a file of its own:
-
+This will overwrite a previous output file whenever it is called; if you
+need to write more than one expression, you would use a variable for
+your port and reuse it:
 @example
 @{
-  #(with-output-to-file "display.txt"
-      (lambda () #@{ \displayMusic @{ c'4\f @} #@}))
+  port = #(open-output-file "display.txt")
+  \displayMusic \port @{ c'4\f @}
+  \displayMusic \port @{ d'4 @}
+  #(close-output-port port)
 @}
 @end example
 
+Guile's manual describes ports in detail.  Closing the port is actually
+only necessary if you need to read the file before Lilypond finishes; in
+the first example, we did not bother to do so.
 
 A bit of reformatting makes the above information easier to read: