If else control flow operator

Recipes & Guides
1

Since Kakoune doesn’t have if else control flow operator I’ve decided to add it myself:

try %{ require-module kak }
add-highlighter shared/kakrc/code/if_else regex \b(if|else)\b 0:keyword

define-command -docstring "if <condition> <expression> [else [if <condition>] <expression>]: if statement that accepts shell-valid condition string" \
if -params 2.. %{ evaluate-commands %sh{
    while [ true ]; do
        condition="[ $1 ]"
        if [ -n "$3" ] && [ "$3" != "else" ]; then
            printf "%s\n" "fail %{if: unknown operator '$3'}"
        elif [ $# -eq 3 ]; then
            printf "%s\n" "fail %{if: wrong argument count}"
        elif eval $condition; then
            [ -n "${2##*&*}" ] && arg="$2" || arg="$(printf '%s' "$2" | sed 's/&/&&/g')"
            printf "%s\n" "evaluate-commands %& $arg &"
        elif [ $# -eq 4 ]; then
            [ -n "${4##*&*}" ] && arg="$4" || arg="$(printf '%s' "$4" | sed 's/&/&&/g')"
            printf "%s\n" "evaluate-commands %& $arg &"
        elif [ $# -gt 4 ]; then
            if [ "$4" = "if" ]; then
                shift 4
                continue
            else
                printf "%s\n" "fail %{if: wrong argument count}"
            fi
        fi
        exit
    done
}}

Primary usage for me is to separate my desktop and mobile configurations, since I don’t want to use some plugins on mobile phone, like kak-lsp or tagbar.kak. Maybe someone will find it useful too.

4 Likes
2

You use Kakoune on your phone?!

3

This is cool, thanks for posting.
I guess it can simplify code a bit, if you only need to shell out for an if.
I wonder if there’s a way we could do it without a shell expansion. Maybe something using a series of try-catch blocks?

Figured I’d add the relevant issue for reference.
While I agree with keeping kakscript minimal, if this is something people are going to start using, IMO it should just be added to Kakoune.

@robertmeta Ya, it’s available on Termux!

4

Yeah, and not only Kakoune but also Emacs. Before using Kakoune there was Vim and NeoVim, and because I’ve used those on phone I’ve developed a snippet plugin for Vim because UltiSnips and SnipMate were really slow on the phone. plug.kak and fzf.kak, as well as my other plugins, were mostly developed on the phone. I waste two and a half hours each day in subway riding to work and back home so I’m trying to use most of this time for something useful (by making plugins, oh… what am I doing with my life… JK)

5

Small update.

I’ve added support for the else if construct. Now it is possible to chain if into else like so:

if %[ -n "$(command -v xsel)" ] %{
    # set xsel mappings
    map -docstring "cut to system clipboard" global user 'd' '|xsel -b -i<ret>'
    # ...
} else if %[ -n "$(command -v xclip)" ] %{
    # set xclip mappings...
} else %{
    echo -debug "neither xsel nor xclip is available"
}

I’ve updated the code in the main comment