type: {
            layout: list
            page_size: 10
        }
        style: {
            text: green
            selected_text: green_reverse
            description_text: yellow
        }
        source: { |buffer, position|
            scope variables
            | where name =~ $buffer
            | sort-by name
            | each { |row| {value: $row.name description: $row.type} }
        }
      }
      ...
    ]
    ...
```

As you can see, the new menu is identical to the `history_menu` previously
described. The only huge difference is the new field called [`source`](/commands/docs/source.md). The
[`source`](/commands/docs/source.md) field is a nushell definition of the values you want to display in the
menu. For this menu we are extracting the data from `scope variables` and we
are using it to create records that will be used to populate the menu.

The required structure for the record is the next one

```nu
{
  value:       # The value that will be inserted in the buffer
  description: # Optional. Description that will be display with the selected value
  span: {      # Optional. Span indicating what section of the string will be replaced by the value
    start:
    end:
  }
  extra: [string] # Optional. A list of strings that will be displayed with the selected value. Only works with a description menu
}
```

For the menu to display something, at least the `value` field has to be present
in the resulting record.

In order to make the menu interactive, these two variables are available in
the block: `$buffer` and `$position`. The `$buffer` contains the value captured
by the menu, when the option `only_buffer_difference` is true, `$buffer` is the
text written after the menu was activated. If `only_buffer_difference` is
false, `$buffer` is all the string in line. The `$position` variable can be
used to create replacement spans based on the idea you had for your menu. The
value of `$position` changes based on whether `only_buffer_difference` is true
or false. When true, `$position` is the starting position in the string where
text was inserted after the menu was activated. When the value is false,
`$position` indicates the actual cursor position.

Using this information, you can design your menu to present the information you
require and to replace that value in the location you need it. The only thing
extra that you need to play with your menu is to define a keybinding that will
activate your brand new menu.

### Menu Keybindings

In case you want to change the default way both menus are activated, you can
change that by defining new keybindings. For example, the next two keybindings
assign the completion and history menu to `Ctrl+t` and `Ctrl+y` respectively

```nu
  $env.config = {
    ...

    keybindings: [
      {
        name: completion_menu
        modifier: control
        keycode: char_t
        mode: [vi_insert vi_normal]
        event: {
          until: [
            { send: menu name: completion_menu }
            { send: menupagenext }
          ]
        }
      }
      {
        name: history_menu
        modifier: control
        keycode: char_y
        mode: [vi_insert vi_normal]
        event: {
          until: [
            { send: menu name: history_menu }
            { send: menupagenext }
          ]
        }
      }
    ]

    ...
  }
```