Rewrite git-slurp to have "some" style

 *  Die by dedicated function.

 *  Push only if allowed (a line containing single word PUSH found in
    .git-slurp-ok file)

 *  Allow working when deeper in git repo (but not if outside).

 *  Make permisson code readable (self-doc).

 *  Enclose in main() to allow for better hygiene.

dotfiles/gittum/bin/slurp

@@ -4,8 +4,8 @@
 # Slurp - add everything, slurp into a WIP commit and push
 #
 
-test -f .git-slurp-ok || {
-    echo "you don't want this." >&2
+die() {
+    echo "$@" >&2
     exit 2
 }
 
@@ -18,6 +18,34 @@ mkmsg() {
     echo "WIP slurp, $date at $host"
 }
 
-git add .
-git commit -m "$(mkmsg)"
-git push
+allowed_anything() {
+    #
+    # Is anything allowed in this repo?
+    #
+    test -f "$ok_file"
+}
+
+allowed_push() {
+    #
+    # Is push allowed in this repo?
+    #
+    grep -qxF PUSH "$ok_file"
+}
+
+main() {
+    local git_root
+    local ok_file
+    local want_push=false
+
+    git_root="$(git rev-parse --show-toplevel)" || die
+    ok_file="$git_root/.git-slurp-ok"
+
+    allowed_anything || die "you don't want this."
+    allowed_push     && want_push=true
+
+    git add .
+    git commit -m "$(mkmsg)"
+    $want_push && git push
+}
+
+main