Some time ago I found xonsh which is a python-based shell. It had really good multiline support, and I am searching for a shell with sameish multiline support as xonsh. Fish shell also has good multiline support, it is around the same level, but it is not posix compatible. I want a shell that has that kind of level of multiline, but zsh (bash is also fine) compatible.

Does anyone know of one?

edit: based on the replies, I get this is unclear. My problem with zsh is that if i press enter and it starts a new line, I can’t get back to the prevous line, because a new prompt is started. In fish this is possible, all lines are one prompt. But, fish is not posix compatible. So, I guess I want a posix-compatible shell with fish-like lines (multiple line) editing. I wanted zsh support to keep using my custom oh-my-zsh prompt, but remaking it for a new shell is not a big problem. Sorry for being unclear.

edit 2: solution is here! Thanks to @andy@programming.dev I started thinking and made the following: When on the first line, enter accepts and alt-enter inserts a newline. When not on the first line, enter inserts a newline and alt-enter accepts. Here is the code to put in your .zshrc:

# MULTILINE!!!
bindkey '^[e' push-line-or-edit

# enter accepts when only one line found, else creates newline
function _zle_ml_enter {
    if ! [[ $BUFFER == *$'\n'* ]]; then
        zle accept-line
    else
        zle self-insert-unmeta
    fi
}
zle -N _zle_ml_enter
bindkey '^M' _zle_ml_enter

# alt-enter accepts when more than one line found, else creates newline
function _zle_ml_meta_enter {
    if [[ $BUFFER == *$'\n'* ]]; then
        zle accept-line
    else
        zle self-insert-unmeta
    fi
}
zle -N _zle_ml_meta_enter
bindkey '^[^M' _zle_ml_meta_enter

edit:
changed if [[ "$BUFFERLINES" -le 1 ]]; then to if ! [[ $BUFFER == *$'\n'* ]]; then and if [[ "$BUFFERLINES" -gt 1 ]]; then to if [[ $BUFFER == *$'\n'* ]]; then for improving detection. Also added alt-e shortcut because I had that configured myself but forgot to add here.

    • Andy@programming.dev
      1·
      1 year ago

      OK, well FWIW in Zsh you can use a keybind to trigger ZLE functions that turn your already-entered lines back into in-progress lines.

      The most straightforward built-in function for this is push-line-or-edit:

      At the top-level (PS1) prompt, equivalent to push-line. At a secondary (PS2) prompt, move the entire current multiline construct into the editor buffer. The latter is equivalent to push-input followed by get-line.

      So let’s say you want to trigger this with ctrl+e, all you need is:

      bindkey '^e' push-line-or-edit
      • vosjedev@lemm.eeOP
        1·
        1 year ago

        Thanks for your reply! This made me think: could I bind enter to newline and alt-enter to accept, which then made me think if it was possible to have enter to accept and alt-enter to newline on first line only, after that in reverse. That made me think of the script I added to the post.

        But serious, without this I would have never thought of doing what I did.

        • Andy@programming.dev
          0·
          1 year ago

          I started using this, it makes a lot of sense and I like it, thanks!

          I can imagine myself forgetting how to accept multiline input with alt+enter, so I added a help message to _zle_ml_enter in the multiline case after the second line. It assumes setopt interactivecomments is already set:

          EDIT: note that lemmy mangles the less-than symbol

          # -- Run input if single line, otherwise insert newline --
# Key: enter
# Assumes: setopt interactivecomments
# Credit: https://programming.dev/comment/2479198
.zle_accept-except-multiline () {
  if (( BUFFERLINES <= 1 )) {
    zle accept-line
  } else {
    zle self-insert-unmeta
    if (( BUFFERLINES == 2 )) {
      LBUFFER+="# Use alt+enter to submit this multiline input"
      zle self-insert-unmeta
    }
  }
}
zle -N .zle_accept-except-multiline
bindkey '^M' .zle_accept-except-multiline  # Enter
          • vosjedev@lemm.eeOP
            2·
            1 year ago

            So I changed some other things to improve detection. I will update the post. But nice idea adding a hint! I personaly did that in a hint command also specifying other shortcuts and aliases about my zsh config.

            • Andy@programming.dev
              1·
              1 year ago

              Thanks again for posting your improvements! I will have them!

              The idea here, checking for newline characters rather than counting lines, is to prevent it treating one line that is so long it wraps to the next as counting as a multiline input, right? So now I’m looking like

              # -- Run input if single line, otherwise insert newline --
# Key: enter
# Assumes: setopt interactivecomments
# Credit: https://programming.dev/comment/2479198
.zle_accept-except-multiline () {
  if [[ $BUFFER != *$'\n'* ]] {
    zle accept-line
    return
  } else {
    zle self-insert-unmeta
    if [[ $BUFFER == *$'\n'*$'\n'* ]] {
      local hint="# Use alt+enter to submit this multiline input"
      if [[ $BUFFER != *${hint}* ]] {
        LBUFFER+=$hint
        zle self-insert-unmeta
      }
    }
  }
}
zle -N .zle_accept-except-multiline
bindkey '^M' .zle_accept-except-multiline  # Enter

# -- Run input if multiline, otherwise insert newline --
# Key: alt+enter
# Credit: https://programming.dev/comment/2479198
.zle_accept_only_multiline () {
  if [[ $BUFFER == *$'\n'* ]] {
    zle accept-line
  } else {
    zle self-insert-unmeta
  }
}
zle -N .zle_accept_only_multiline
bindkey '^[^M' .zle_accept_only_multiline  # Enter

              For pushing the line/multiline, I combine it with my clear function (ctrl+l):

              # -- Refresh prompt, rerunning any hooks --
# Credit: romkatv/z4h
.zle_redraw-prompt () {
  for 1 ( chpwd $chpwd_functions precmd $precmd_functions ) {
    if (( $+functions[$1] ))  $1 &>/dev/null
  }
  zle .reset-prompt
  zle -R
}

# -- Better Screen Clearing --
# Clear line and redraw prompt, restore line at next prompt
# Key: ctrl+l
# Depends: .zle_redraw-prompt
.zle_push-line-and-clear () { zle push-input; zle clear-screen; .zle_redraw-prompt }
zle -N       .zle_push-line-and-clear
bindkey '^L' .zle_push-line-and-clear  # ctrl+l