The core of a ENiGMA½ based BBS is it's menus driven by what will be referred to as `menu.hjson`. Throughout ENiGMA½ documentation, when `menu.hjson` is referenced, we're actually talking about `config/menus/yourboardname-*.hjson`. These files determine the menus (or screens) a user can see, the order they come in, how they interact with each other, ACS configuration, and so on. Like all configuration within ENiGMA½, menu configuration is done in [HJSON](https://hjson.org/) format.
> :bulb: Entries in `menu.hjson` are often referred to as *blocks* or *sections*. Each entry defines a menu. A menu in this sense is something the user can see or visit. Examples include but are not limited to:
Menu entries live under the `menus` section of `menu.hjson`. The *key* for a menu is it's name that can be referenced by other menus and areas of the system.
> :information_source: Remember that the top level menu may include additional files using the `includes` directive. See [Configuration Files](config-files.md) for more information on this.
Below is a table of **common** menu entry members. These members apply to most entries, though entries that are backed by a specialized module (ie: `module: bbs_list`) may differ. Menus that use their own module contain a `module` declaration:
```hjson
module: some_fancy_module
```
See documentation for the module in question for particulars.
| `next` | Specifies the menu to go to next. Can be explicit or an array of possibilities dependent on ACS. See **Flow Control** in the **ACS Checks** section below. If `next` is not supplied, the next menu is this menus parent. Note that special built in methods such as `@systemMethod:logoff` can also be utilized here. |
| `prompt` | Specifies a prompt, by name, to use along with this menu. Prompts are configured in the `prompts` section. See **Prompts** for more information. |
The `menuFlags` field of a `config` block can change default behavior of a particular menu.
| Flag | Description |
|------|-------------|
| `noHistory` | Prevents the menu from remaining in the menu stack / history. When this flag is set, when the **next** menu falls back, this menu will be skipped and the previous menu again displayed instead. Example: menuA -> menuB(noHistory) -> menuC: Exiting menuC returns the user to menuA. |
| `popParent` | When *this* menu is exited, fall back beyond the parent as well. Often used in combination with `noHistory`. |
| `forwardArgs` | If set, when the next menu is entered, forward any `extraArgs` arguments to *this* menu on to it. |
ENiGMA½ uses a concept of *forms* in menus. A form is a collection of associated *views*. Consider a New User Application using the `nua` module: The default implementation utilizes a single form with multiple EditTextView views, a submit button, etc. Forms are identified by number starting with `0`. A given menu may have mutiple forms (often associated with different states or screens within the menu).
Menus may also support more than one layout type by using a *MCI key*. A MCI key is a alpha-numerically sorted key made from 1:n MCI codes. This lets the system choose the appropriate set of form(s) based on theme or random art. An example of this may be a matrix menu: Perhaps one style of your matrix uses a vertical light bar (`VM` key) while another uses a horizontal (`HM` key). The system can discover the correct form to use by matching MCI codes found in the art to that of the available forms defined in `menu.hjson`.
When a form is submitted, it's data is matched against a *submit handler*. When a match is found, it's *action* is performed. Note: Setting the value explicitly to null matches against any value.
Submit actions are declared using the `action` member of a submit handler block. Actions can be kick off system/global or local-to-module methods, launch other menus, etc.
| Action | Description |
|--------|-------------|
| `@menu:menuName` | Takes the user to the *menuName* menu |
| `@systemMethod:methodName` | Executes the system/global method *methodName*. See **System Methods** below. |
| `@method:methodName` | Executes *methodName* local to the calling module. That is, the module set by the `module` member of a menu entry. |
| `@method:/path/to/some_module.js:methodName` | Executes *methodName* exported by the module at */path/to/some_module.js*. |
In addition to simple simple actions, `action` may also be:
* An array of objects containing ACS checks and a sub `action` if that ACS is matched. See **Action Matches** in the ACS documentation below for details.
* An array of actions. In this case a random selection will be made. Example:
The above entry `telnetConnected` is set as the Telnet server's first menu entry (set by `firstMenu` in the Telnet server's config). The entry sets up a few things:
In the above entry, you'll notice `form`. This defines a form(s) object. In this case, a single form by ID of `0`. The system is then told to use a block only when the resulting art provides a `VM` (*VerticalMenuView*) MCI entry. Some other bits about the form:
*`VM1` is then setup to `submit` and start focused via `focus: true` as well as have some menu entries ("login", "apply", ...) defined. We provide an `argName` of `matrixSubmit` for this element view.
* The `submit` object tells the system to attempt to apply provided match entries from any view ID (`*`).
* Upon submit, the first match will be executed. For example, if the user selects "login", the first entry with a value of `{ matrixSubmit: 0 }` will match (due to 0 being the first index in the list and `matrixSubmit` being the arg name in question) causing `action` of `@menu:login` to be executed (go to `login` menu).
Prompts are found in the `prompts` section of menu files. Prompts allow for quick user input and shorthand form requirements for menus. Additionally, prompts are often used for for multiple menus. Consider a pause prompt or menu command input for example.
The `next` member of a menu may be an array of objects containing an `acs` check as well as the destination. Depending on the current user's ACS, the system will pick the appropriate target. The last element in an array without an `acs` can be used as a catch all. Example:
A very common task: You want to add a new menu accessible from "Main". First, let's create a new menu called "Snazzy Town"! Perhaps under the `mainMenu` entry somewhere, create a new menu:
```hjson
snazzyTown: {
desc: Snazzy Town
art: snazzy
config: {
cls: true
pause: true
}
}
```
Now let's make it accessible by "S" from the main menu. By default the main menu entry is named `mainMenu`. Within the `mainMenu`'s `submit` block you will see some existing action matches to "command". Simply add a new one pointing to `snazzyTown`:
```hjson
{
value: { command: "S" }
action: @menu:snazzyTown
}
```
That's it! When users type "S" at the main menu, they'll be sent to the Snazzy Town menu. Since we did not supply additional flow logic when they exit, they will fall back to main.
You've got a super 31337 board and want to prevent lamerz! Let's run through adding a NUP to your application flow.
Given the default menu system, two "pre" new user application menus exist due to the way Telnet vs SSH logins occur. We'll focus only on Telnet here. This menu is `newUserApplicationPre`. Let's say you want to display this preamble, but then ask for the NUP. If the user gets the password wrong, show them a `LAMER.ANS` and boot 'em.
// here we use a built in system method to boot them.
next: @systemMethod:logoff
config: {
// wait 2s after showing the art before kicking them
nextTimeout: 2000
}
}
```
Great, we have a couple new menus. Now let's just point to them. Remember the existing `newUserApplicationPre` menu? All that is left to do is point it's `next` to our `newUserPassword` menu:
```hjson
newUserApplicationPre: {
// easy! Just tell the system where to go next
next: newUserPassword
// note that the rest of this menu is omitted for clarity
Enigma½ tries to automatically determine the proper encoding for a client when it connects. Unfortunately, there are cases where the wrong encoding can be selected, resulting in terminal programs that are not supported. If your user base contains users that would like to connect with unsupported clients, one solution is to offer manual encoding selection.
*Note*: This example can be shortened by using @reference sections if desired.
The `acs:` sections above will send the user to a different menu depending on whether they have encoding CP437 using `EC0` or anything else sent to the UTF8 menu. From there `focusItemIndex` chooses the default item.
