Add script to regenerate freeze files

regen-freeze-files.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+
+set -eu
+
+status_message() {
+    printf "\\033[0;32m%s\\033[0m\\n" "$1"
+}
+
+warning_message() {
+    printf "\\033[1;33m%s\\033[0m\\n" "$1"
+}
+
+shopt -s extglob
+
+cabal v2-update --write-ghc-environment-files=never
+
+for project_file in cabal.project.!(*.freeze) ; do
+    unset ghc_ver freeze_file
+    ghc_ver=${project_file#cabal.project.}
+    freeze_file=${project_file}.freeze
+    if command -V ghc-${ghc_ver} >/dev/null 2>&1 ; then
+        status_message "Generating ${freeze_file}"
+        [ -f "${freeze_file}" ] && rm "${freeze_file}"
+        cabal v2-freeze \
+            --write-ghc-environment-files=never \
+            -w ghc-${ghc_ver} \
+            --project-file=${project_file}
+        awk "
+          BEGIN{print \"with-compiler: ghc-${ghc_ver}\n\"}
+          {print \$0}" "${freeze_file}" > "${freeze_file}.tmp"
+        mv "${freeze_file}.tmp" "${freeze_file}"
+    else
+        warning_message "Missing ghc-${ghc_ver}, skipping freeze file generation"
+    fi
+done
+
+# vim: tabstop=4 shiftwidth=4 expandtab
+