mless: doesn't work on OpenBSD 7.6 due to lack of LESSOPEN

[leahneukirchen]

LESSOPEN support was removed in OpenBSD in openbsd/src@c74702f

I'm not sure how we can have something like mless without this feature... one would need to pre-render the whole sequence perhaps?

[josephchoe]

That might result in performance problems for large sequences. I've just gotten around it by piping a message with the preamble into less, though that doesn't allow me to page through mail, but oh well.

[leahneukirchen]

One approach could be to drive less in a loop, and use exit codes to switch between files, only starting less with one mail rendered every time.

[josephchoe]

Hrm, I'm assuming that this would have different keybindings than lesskey(1)?

I looked at the source for less(1) on OpenBSD, and exit codes seem to be here: https://github.com/openbsd/src/blob/master/usr.bin/less/less.h#L157-L159

So, 0 for success, 1 for error, and 2 for interrupt. Not a whole lot of wiggle room to switch between specific files. Unless there's something I'm missing?

[leahneukirchen]

e.g. add Z quit \42 to .lesskey, run lesskey, press Z in less, it exits with status 34 (=042).

Works on OpenBSD 7.6.

[josephchoe]

Is something like this what you had in mind?

diff --git a/mless b/mless
index ddead98..51bd361 100755
--- a/mless
+++ b/mless
@@ -85,10 +85,26 @@ elif [ -f "$HOME/.mblaze/mless" ]; then
 elif [ -f "$HOME/.mless" ]; then
 	export LESSKEY="$HOME/.mless"
 fi
+scan=0
 while :; do
-	LESSOPEN="|$0 --filter %s" \
-		less -Ps"mless %f?m (message %i of %m).." -R \
-			"+:e $(mscan -n .)$nl" //scan $(mscan -n :)
+	local cur=$(mscan -n .)
+	local total=$(mscan -n : | tail -1)
+
+	if [ $scan -ne 0 ]
+	then
+		cur="//scan"
+		local status="mless.."
+	else
+		local status="mless $cur (message $cur of $total).."
+	fi
+
+	{
+		case $cur in
+			[0-9]*) $0 --filter $cur;;
+			*) $0 --filter //scan;;
+		esac
+	} | less -Ps"$status" -R
+
 	case "$?" in
 	0|1) exit $?;;
 	36) # $ goto end
@@ -111,6 +127,21 @@ while :; do
 	72) # H toggle HTML mode
 		MLESS_HTML=$((1-$MLESS_HTML))
 		;;
+	91) # [ prev file
+		case $cur in
+			1) scan=1;;
+			*) mseq -C '.-1' 2>/dev/null;;
+		esac
+		;;
+	93) # ] next file
+		if [ $scan -eq 0 ]
+		then
+			mseq -C '.+1' 2>/dev/null
+		else
+			scan=0
+			mseq -C 1 2>/dev/null
+		fi
+		;;
 	94) # ^ goto parent
 		mseq -C '.^' 2>/dev/null
 		;;
diff --git a/mlesskey.example b/mlesskey.example
index be82e1d..90d69af 100644
--- a/mlesskey.example
+++ b/mlesskey.example
@@ -4,8 +4,8 @@
 # When using less >=590: copy this file to ~/.mlesskey
 Q quit \1
 :cq quit \1
-[ prev-file
-] next-file
+[ quit [
+] quit ]
 { noaction E1\n
 } quit $
 $ quit $