workaround popen trouble on windows

footer_with_songinfo.ly

@@ -10,7 +10,9 @@
         (assoc-ref author "death_year")
         (assoc-ref author "organization")
       )
-      "unbekannt")))
+      (if (string-null? authorId)
+          "unbekannt"
+          authorId))))
 
 #(define (find-author-ids-by contributionType authors)
   (if authors

scm/yaml_parser.scm

@@ -1,12 +1,22 @@
-(use-modules (ice-9 popen) (ice-9 textual-ports) (json parser))
+(if (not windows?) (use-modules (ice-9 popen)))
+(use-modules (ice-9 textual-ports) (json parser))
 
 (define (yml-file->scm filename)
-  (let* ((python_cmd (string-append "import sys, yaml, json; print(json.dumps(yaml.safe_load(open('" filename "'))))"))
-          ; WTF? On Windows there is "py" and we need to specify the encoding, on linux there is "python3" or "python"
-          ; but "python3" seems to work better. Be sure you have PyYAML installed.
-          (pipe (open-pipe (string-append "PYTHONHOME='' " (if windows? "py" "python3") " -X utf8 -c \"" python_cmd "\"") OPEN_READ))
-          (json (get-string-all pipe)))
-    (close-pipe pipe)
-    (json-string->scm json)))
+  (if windows?
+    (let* ((tmpdir (or (getenv "TMPDIR") (getenv "TEMP") "/tmp"))
+            (port (mkstemp (string-append tmpdir "\\" (basename filename) "-XXXXXX") "r"))
+            (tmpfilepath (port-filename port))
+            (python_code (string-append "import sys, yaml, json; f = open('" tmpfilepath "', 'w'); f.write(json.dumps(yaml.safe_load(open('" filename "')))); f.close()"))
+            (status (system (string-append "py -X utf8 -c \"" python_code "\"")))
+            (json (get-string-all port)))
+      (delete-file tmpfilepath)
+      (json-string->scm (if (status:exit-val status) json "{}")))
+    (let* ((python_code (string-append "import sys, yaml, json; print(json.dumps(yaml.safe_load(open('" filename "'))))"))
+            ; WTF? On Windows there is "py" and we need to specify the encoding, on linux there is "python3" or "python"
+            ; but "python3" seems to work better. Be sure you have PyYAML installed.
+            (pipe (open-pipe (string-append "PYTHONHOME='' " (if windows? "py" "python3") " -X utf8 -c \"" python_code "\"") OPEN_READ))
+            (json (get-string-all pipe)))
+      (close-pipe pipe)
+      (json-string->scm json))))
 
 (define (parse-yml-file filename) (resolve-inherits (yml-file->scm filename)))