isabelle_stack as portable shell function;

--- a/Admin/components/components.sha1	Wed Oct 17 16:53:45 2018 +0200
+++ b/Admin/components/components.sha1	Wed Oct 17 20:06:19 2018 +0200
@@ -226,6 +226,7 @@
 27aeac6a91353d69f0438837798ac4ae6f9ff8c5  sqlite-jdbc-3.23.1.tar.gz
 8d20968603f45a2c640081df1ace6a8b0527452a  sqlite-jdbc-3.8.11.2.tar.gz
 2369f06e8d095f9ba26df938b1a96000e535afff  ssh-java-20161009.tar.gz
+fdc415284e031ee3eb2f65828cbc6945736fe995  stack-1.9.1.tar.gz
 1f4a2053cc1f34fa36c4d9d2ac906ad4ebc863fd  sumatra_pdf-2.1.1.tar.gz
 601e08d048d8e50b0729429c8928b667d9b6bde9  sumatra_pdf-2.3.2.tar.gz
 14d46c2eb1a34821703da59d543433f581e91df3  sumatra_pdf-2.4.tar.gz

--- a/Admin/components/main	Wed Oct 17 16:53:45 2018 +0200
+++ b/Admin/components/main	Wed Oct 17 20:06:19 2018 +0200
@@ -19,6 +19,7 @@
 spass-3.8ds-1
 sqlite-jdbc-3.23.1
 ssh-java-20161009
+stack-1.9.1
 vampire-4.2.2
 xz-java-1.8
 z3-4.4.0pre-2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Admin/haskell/stack/README	Wed Oct 17 20:06:19 2018 +0200
@@ -0,0 +1,12 @@
+This is stack 1.9.1 -- the Haskell Tool Stack.
+
+See also https://www.haskellstack.org and executables from
+https://github.com/commercialhaskell/stack/releases as follows:
+
+  * x86_64-linux: stack-1.9.1-linux-x86_64-static.tar.gz
+  * x86_64-darwin: stack-1.9.1-osx-x86_64.tar.gz
+  * x86_64-windows: stack-1.9.1-windows-x86_64.tar.gz
+
+
+    Makarius
+    17-Oct-2018

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Admin/haskell/stack/settings	Wed Oct 17 20:06:19 2018 +0200
@@ -0,0 +1,3 @@
+# -*- shell-script -*- :mode=shellscript:
+
+ISABELLE_STACK="$COMPONENT/${ISABELLE_WINDOWS_PLATFORM64:-$ISABELLE_PLATFORM64}/stack"

--- a/etc/settings	Wed Oct 17 16:53:45 2018 +0200
+++ b/etc/settings	Wed Oct 17 20:06:19 2018 +0200
@@ -142,6 +142,13 @@
 
 
 ###
+### Haskell
+###
+
+ISABELLE_STACK_ROOT="$ISABELLE_HOME_USER/stack"
+
+
+###
 ### Misc settings
 ###
 

--- a/lib/scripts/getfunctions	Wed Oct 17 16:53:45 2018 +0200
+++ b/lib/scripts/getfunctions	Wed Oct 17 20:06:19 2018 +0200
@@ -37,6 +37,18 @@
 }
 export -f isabelle_opam
 
+#Haskell management via Stack
+function isabelle_stack()
+{
+  if [ -z "$ISABELLE_STACK" ]; then
+    echo "Unknown ISABELLE_STACK -- Haskell management tools unavailable" >&2
+    return 127
+  else
+    env STACK_ROOT="$(platform_path "$ISABELLE_STACK_ROOT")" "$ISABELLE_STACK" "$@"
+  fi
+}
+export -f isabelle_stack
+
 #robust invocation via ISABELLE_JDK_HOME
 function isabelle_jdk ()
 {