diff --git a/lib/chibi/app.scm b/lib/chibi/app.scm
index 08c1ed4a..3380ffe2 100644
--- a/lib/chibi/app.scm
+++ b/lib/chibi/app.scm
@@ -33,6 +33,13 @@
          (if (not (= 1 (string-length str)))
              (list #f "expected a single character")
              (list (string-ref str 0) #f)))
+        ((sexp)
+         (list (guard (exn (else str))
+                 (let* ((in (open-input-string str))
+                        (res (read in)))
+                   (close-input-port in)
+                   res))
+               #f))
         (else
          (list str #f))))))
   (define (lookup-conf-spec conf-spec syms strs)
diff --git a/lib/chibi/app.sld b/lib/chibi/app.sld
index 585cfc95..0ec087e4 100644
--- a/lib/chibi/app.sld
+++ b/lib/chibi/app.sld
@@ -3,6 +3,7 @@
   (export parse-option parse-options parse-app run-application
           app-help app-help-command)
   (import (scheme base)
+          (scheme read)
           (scheme write)
           (scheme process-context)
           (srfi 1)