# HG changeset patch
# User wenzelm
# Date 1677767961 -3600
# Node ID 1082f0d6628bbf9220c024dbae7085faf207200c
# Parent  abc9706a4ca2da8ef04b8f0468ea146a10870854
tuned;

diff -r abc9706a4ca2 -r 1082f0d6628b src/Pure/ML/ml_process.scala
--- a/src/Pure/ML/ml_process.scala	Thu Mar 02 15:39:14 2023 +0100
+++ b/src/Pure/ML/ml_process.scala	Thu Mar 02 15:39:21 2023 +0100
@@ -117,9 +117,10 @@
     bash_env.put("ISABELLE_TMP", File.standard_path(isabelle_tmp))
     bash_env.put("POLYSTATSDIR", isabelle_tmp.getAbsolutePath)
 
-    val policy = options.string("ML_process_policy") match { case "" => "" case s => s + " " }
+    val process_policy = options.string("ML_process_policy")
+    val process_prefix = if_proper(process_policy, process_policy + " ")
 
-    Bash.process(policy + """"$ML_HOME/poly" -q """ + Bash.strings(bash_args),
+    Bash.process(process_prefix + """"$ML_HOME/poly" -q """ + Bash.strings(bash_args),
       cwd = cwd,
       env = bash_env,
       redirect = redirect,