A ZLE widget for calculator

Hey!

I currently have this code in my zshrc:

# Simple calculator
_vbe_calc_accept_line() {
     local expr
     case $BUFFER in
         "= "*) expr=${BUFFER#= } ;;
     esac
     case $expr in
         "") ;;
         \'*) BUFFER="= ${(q-)${(Q)expr}}" ;;
         *) BUFFER="= ${(q-)expr}"
     esac
     zle .accept-line
}
zle -N accept-line _vbe_calc_accept_line
aliases[=]='numbat -e'

When I use the "=" alias, it will automatically quote what's after. This 
is better than noglob.

  08:12 ❱ = 1
1
  08:12 ❱ = 1+2
3
  08:12 ❱ = 'today() + 3 days'
2026-02-06 00:00:00 CET (UTC +01), Europe/Paris
  08:12 ❱ = '47 km/h to miles/h'
29.2044 mi/h

This seems a bit clunky to detect when something was quoted and undo it. 
Ideally, I would like to have the quoted alias executed, but for history 
and display purpose keep the buffer unchanged.

# Simple calculator
_vbe_calc_accept_line() {
     if [[ $BUFFER =~ "= *" ]]; then
         local expr=${BUFFER#= }
         zle -I
         command numbat -e "$expr"
         print
         print -s $BUFFER
         BUFFER=""
     else
         zle .accept-line
     fi
}
zle -N accept-line _vbe_calc_accept_line

It almost work, but the buffer is not available in the immediate history 
(because no accept-line was called). If I press the up arrow, I get the 
previous one instead.

Any idea?

Thanks!