Fix shgit shell style and reenable it

dotfiles/shrc

@@ -30,11 +30,17 @@ if [ -d ~/local/man ]; then
 	alias man="/usr/bin/man -m ~/local/man"
 fi
 
+PS1=
+if [ -f ~/code/lucas/env/utils/shgit ]; then
+	. ~/code/lucas/env/utils/shgit
+	export PS1='$(shgit)'
+fi
+
 case $SHELL in
 /bin/mksh)
-	PS1='${HOSTNAME:=$(hostname -s)}\$ '
+	PS1=$PS1'${HOSTNAME:=$(hostname -s)}\$ '
 	;;
-*)	PS1='\h\$ '
+*)	PS1=$PS1'\h\$ '
 	;;
 esac
 export PS1

utils/shgit

@@ -1,4 +1,4 @@
-# env
+# shgit
 # Written in 2019 by Lucas
 # CC0 1.0 Universal/Public domain - No rights reserved
 #
@@ -9,20 +9,24 @@
 # Dedication along with this software. If not, see
 # <http://creativecommons.org/publicdomain/zero/1.0/>.
 
-shgit() {
-	if ! gitdir=$(git rev-parse --git-dir 2>/dev/null) \
-	    || [ -z "$gitdir" ]; then
-		return
-	fi
+shgit()
+{
+	: ${SHGIT_BEGIN:=} ${SHGIT_END:= } ${SHGIT_SEP:=:}
+
+	gitdir=$(git rev-parse --git-dir 2>/dev/null) && [ -n "$gitdir" ] ||
+	    return
 
 	symbolic=$(git symbolic-ref --short HEAD 2>/dev/null)
-	hash=$(git rev-parse --short HEAD 2>/dev/null)
-	name=${symbolic:-${hash:-"?"}}
+	name=${symbolic:-}
+	if [ -z "$name" ]; then
+		hash=$(git rev-parse --short HEAD 2>/dev/null)
+		name=${hash:-"?"}
+	fi
 
 	rb=
 	rbdir="$gitdir/rebase-merge"
 	if [ -d "$rbdir" ]; then
-		rb="REBASE"
+		rb="${SHGIT_SEP}REBASE"
 		read -r name <"$rbdir/head-name"
 		name=${name##*/}
 		[ -f "$rbdir/interactive" ] && rb="$rb-i"
@@ -32,9 +36,7 @@ shgit() {
 	fi
 
 	status=
-	if [ -z "$(git status --porcelain)" ]; then
-		status="*"
-	fi
+	[ -n "$(git status --porcelain)" ] && status="${SHGIT_SEP}*"
 
 	commits=$(git rev-list --left-right --count @{upstream}...HEAD \
 	    2>/dev/null | {
@@ -42,8 +44,8 @@ shgit() {
 		IFS="	" read -r behind ahead
 		[ ${behind:-0} -gt 0 ] && t=$t"v$behind"
 		[ ${ahead:-0} -gt 0 ] && t=$t"^$ahead"
-		printf "%s" "$t"
+		[ -n "$t" ] && printf "%s" "$SHGIT_SEP" "$t"
 	})
 
-	printf "%s" "$name${rb:+:$rb}${status:+:$status}${commits:+:$commits}"
+	printf "%s%s%s" "$SHGIT_BEGIN" "$name$rb$status$commits" "$SHGIT_END"
 }