Implementing the mirror plugin for Kakoune in Dance

keybindings.json

[
    {
        "key": "'",
        "command": "dance.openMenu",
        "args": {
            "menu": "mirror"
        },
        "when": "editorTextFocus && dance.mode == 'normal'"
    },
]

settings.json

    "multiCommand.commands": [
        {
            "command": "multiCommand.mirror.c",
            "sequence": [
                "dance.select.copy",
                "dance.selections.flip",
                "dance.select.copy.backwards",
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.h",
            "sequence": [
                "dance.left.extend",
                "dance.selections.flip",
                "dance.right.extend",
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.l",
            "sequence": [
                "dance.right.extend",
                "dance.selections.flip",
                "dance.left.extend",
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.j",
            "sequence": [
                "dance.down.extend",
                "dance.selections.flip",
                "dance.up.extend",
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.k",
            "sequence": [
                "dance.up.extend",
                "dance.selections.flip",
                "dance.down.extend",
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.J",
            "sequence": [
                "dance.down.extend",
                "dance.selections.flip",
                "dance.up.extend",
                "dance.selections.flip",
                "dance.expandLines",
            ]
        },
        {
            "command": "multiCommand.mirror.K",
            "sequence": [
                "dance.up.extend",
                "dance.selections.flip",
                "dance.down.extend",
                "dance.selections.flip",
                "dance.expandLines",
            ]
        },
        {
            "command": "multiCommand.mirror.b",
            "sequence": [
                "dance.select.word.previous.extend",
                "dance.selections.flip",
                "dance.select.word.extend",
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.w",
            "sequence": [
                "dance.select.word.extend",
                "dance.selections.flip",
                "dance.select.word.previous.extend",
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.e",
            "sequence": [
                "dance.select.word.end.extend",
                "dance.selections.flip",
                "dance.select.word.previous.extend",
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.p",
            "sequence": [
                {"command": "dance.objects.performSelection", "args": {"object": "paragraph", "action": "selectToEnd", "extend": true, "inner": false}},
                "dance.selections.flip",
                {"command": "dance.objects.performSelection", "args": {"object": "paragraph", "action": "selectToStart", "extend": true, "inner": false}},
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.s",
            "sequence": [
                {"command": "dance.objects.performSelection", "args": {"object": "sentence", "action": "selectToEnd", "extend": true, "inner": false}},
                "dance.selections.flip",
                {"command": "dance.objects.performSelection", "args": {"object": "sentence", "action": "selectToStart", "extend": true, "inner": false}},
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.m",
            "sequence": [
                "dance.select.enclosing.extend",
                "dance.selections.flip",
                "dance.select.enclosing.extend.backwards",
                "dance.selections.flip",
            ]
        },
        {
            "command": "multiCommand.mirror.lparen",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": ")"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "("}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.lcurly",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": "}"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "{"}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.lbracket",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": "]"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "["}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.lt",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": ">"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "<"}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.rparen",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": " )"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "( "}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.rcurly",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": " }"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "{ "}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.rbracket",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": " ]"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "[ "}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.gt",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": " >"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "< "}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.doublequote",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": "\""}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "\""}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.singlequote",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": "'"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "'"}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.backtick",
            "sequence": [
                "dance.insert.after",
                {"command": "type", "args": {"text": "`"}}
                "dance.set.normal",
                "dance.marks.saveSelections",   // shouldn't need this
                "dance.insert.before",
                {"command": "type", "args": {"text": "`"}}
                "dance.set.normal",
                "dance.marks.restoreSelections",
                "dance.selections.flip",
                "dance.left.extend",
            ]
        },
        {
            "command": "multiCommand.mirror.d",
            "sequence": [
                "dance.marks.saveSelections",
                "dance.select.firstLast",
                "dance.delete.noYank",
                "dance.marks.restoreSelections",
                "dance.selections.forward",
            ]
        },
    ],
    "dance.menus": {
        "mirror": {
            "items": {
                "c": {
                    "text": "column",
                    "command": "multiCommand.mirror.c",
                },
                "l": {
                    "text": "character left",
                    "command": "multiCommand.mirror.l",
                },
                "h": {
                    "text": "character right",
                    "command": "multiCommand.mirror.h",
                },
                "j": {
                    "text": "line down",
                    "command": "multiCommand.mirror.j",
                },
                "k": {
                    "text": "line up",
                    "command": "multiCommand.mirror.k",
                },
                "J": {
                    "text": "full line down",
                    "command": "multiCommand.mirror.J",
                },
                "K": {
                    "text": "full line up",
                    "command": "multiCommand.mirror.K",
                },
                "b": {
                    "text": "word begin",
                    "command": "multiCommand.mirror.b",
                },
                "w": {
                    "text": "word begin",
                    "command": "multiCommand.mirror.w",
                },
                "e": {
                    "text": "word end",
                    "command": "multiCommand.mirror.e",
                },
                "p": {
                    "text": "paragraph",
                    "command": "multiCommand.mirror.p",
                },
                "s": {
                    "text": "sentence",
                    "command": "multiCommand.mirror.s",
                },
                "m": {
                    "text": "matching",
                    "command": "multiCommand.mirror.m",
                },
                "(": {
                    "text": "(surround)",
                    "command": "multiCommand.mirror.lparen",
                },
                "{": {
                    "text": "{surround}",
                    "command": "multiCommand.mirror.lcurly",
                },
                "[": {
                    "text": "[surround]",
                    "command": "multiCommand.mirror.lbracket",
                },
                "<": {
                    "text": "<surround>",
                    "command": "multiCommand.mirror.lt",
                },
                ")": {
                    "text": "( surround )",
                    "command": "multiCommand.mirror.rparen",
                },
                "}": {
                    "text": "{ surround }",
                    "command": "multiCommand.mirror.rcurly",
                },
                "]": {
                    "text": "[ surround ]",
                    "command": "multiCommand.mirror.rbracket",
                },
                ">": {
                    "text": "< surround >",
                    "command": "multiCommand.mirror.gt",
                },
                "\"": {
                    "text": "\"surround\"",
                    "command": "multiCommand.mirror.doublequote",
                },
                "'": {
                    "text": "'surround'",
                    "command": "multiCommand.mirror.singlequote",
                },
                "`": {
                    "text": "`surround`",
                    "command": "multiCommand.mirror.backtick",
                },
                "d": {
                    "text": "delete surround",
                    "command": "multiCommand.mirror.d",
                },
            }
        }
    }