diff --git a/oni/gexp.scm b/oni/gexp.scm
new file mode 100644
index 0000000..388c7a2
--- /dev/null
+++ b/oni/gexp.scm
@@ -0,0 +1,20 @@
+(define-module (oni gexp)
+  #:use-module (guix gexp)
+
+  #:export (mixed-executable-file))
+
+(define* (mixed-executable-file name #:key guile #:rest text)
+  "Return an object representing store file NAME containing TEXT and having the
+executable bit set. TEXT is a sequence of strings and file-like objects, as in:
+
+  (mixed-executable-file \"profile\"
+                         \"export PATH=\" coreutils \"/bin:\" grep \"/bin\")"
+  (define build
+    (let ((text (if guile (drop text 2) text)))
+      (gexp (call-with-output-file (ungexp output "out")
+              (lambda (port)
+                (set-port-encoding! port "UTF-8")
+                (display (string-append (ungexp-splicing text)) port)
+                (chmod port #o555))))))
+
+  (computed-file name build #:guile guile))
diff --git a/oni/home/services/herbstluftwm.scm b/oni/home/services/herbstluftwm.scm
index e69a17c..26b79c9 100644
--- a/oni/home/services/herbstluftwm.scm
+++ b/oni/home/services/herbstluftwm.scm
@@ -7,6 +7,7 @@
   #:use-module (guix packages)
   #:use-module (guix gexp)
   #:use-module (oni home services xsession)
+  #:use-module (oni gexp)
   #:use-module (srfi srfi-1)
 
   #:export (home-herbstluftwm-service-type
@@ -47,24 +48,6 @@
 (define (add-herbstluftwm-packages config)
   (list (home-herbstluftwm-configuration-package config)))
 
-(define* (mixed-executable-file name #:key guile #:rest text)
-  "Return an object representing store file NAME containing TEXT.  TEXT is a
-sequence of strings and file-like objects, as in:
-
-  (mixed-text-file \"profile\"
-                   \"export PATH=\" coreutils \"/bin:\" grep \"/bin\")
-
-This is the declarative counterpart of 'text-file*'."
-  (define build
-    (let ((text (if guile (drop text 2) text)))
-      (gexp (call-with-output-file (ungexp output "out")
-              (lambda (port)
-                (set-port-encoding! port "UTF-8")
-                (display (string-append (ungexp-splicing text)) port)
-                (chmod port #o555))))))
-
-  (computed-file name build #:guile guile))
-
 (define (home-herbstluftwm-autostart-file config)
   (apply mixed-executable-file
          "autostart"
diff --git a/oni/home/services/xsession.scm b/oni/home/services/xsession.scm
index c6f06e7..9208235 100644
--- a/oni/home/services/xsession.scm
+++ b/oni/home/services/xsession.scm
@@ -4,6 +4,7 @@
   #:use-module (gnu home services utils)
   #:use-module (guix packages)
   #:use-module (guix gexp)
+  #:use-module (oni gexp)
   #:use-module (srfi srfi-1)
 
   #:export (home-xsession-service-type
@@ -20,24 +21,6 @@
    (text-config '())
    "String"))
 
-(define* (mixed-executable-file name #:key guile #:rest text)
-  "Return an object representing store file NAME containing TEXT.  TEXT is a
-sequence of strings and file-like objects, as in:
-
-  (mixed-text-file \"profile\"
-                   \"export PATH=\" coreutils \"/bin:\" grep \"/bin\")
-
-This is the declarative counterpart of 'text-file*'."
-  (define build
-    (let ((text (if guile (drop text 2) text)))
-      (gexp (call-with-output-file (ungexp output "out")
-              (lambda (port)
-                (set-port-encoding! port "UTF-8")
-                (display (string-append (ungexp-splicing text)) port)
-                (chmod port #o555))))))
-
-  (computed-file name build #:guile guile))
-
 (define (xsession-home-files config)
   `((".xsession"
      ,(mixed-executable-file