logic and/or in Verse: Gate Logic for Your Island

Overview

Verse treats and and or as failable-expression combinators, not just boolean operators. Inside an if condition (or any failable context), and requires both sub-expressions to succeed, while or tries each in turn and takes the first success. This maps perfectly onto game logic:

• AND gate — both crew members must stand on their plates before the treasure vault opens.
• OR gate — the captain's override plate OR the two-crew plates open the same vault.

Pair these operators with trigger_device (to fire downstream devices and broadcast events) and hud_message_device (to give players real-time feedback) and you have a fully interactive, readable puzzle system with zero extra blueprint nodes.

Reach for and/or whenever you need multi-condition checks that drive device calls — they keep your if guards compact and intention-clear.

API Reference

trigger_device

Used to relay events to other linked devices.

Full public surface, resolved verbatim from the live Epic digest (Fortnite.digest.verse). Inherited members are merged from trigger_base_device.

trigger_device<public> := class<concrete><final>(trigger_base_device):

Events (subscribe a handler to react):

Methods (call these to make the device act):

player

Full public surface, resolved verbatim from the live Epic digest (Verse.digest.verse). Inherited members are merged from agent.

player<native><public> := class<unique><persistent><module_scoped_var_weak_map_key><epic_internal>(agent):

hud_message_device

Used to show custom HUD messages to one or more agents.

Full public surface, resolved verbatim from the live Epic digest (Fortnite.digest.verse).

hud_message_device<public> := class<concrete><final>(creative_device_base):

Events (subscribe a handler to react):

Methods (call these to make the device act):

Walkthrough

The Scene

You're on a 2D cel-shaded pirate dock at golden hour. Two barnacle-crusted pressure plates sit on the dock planks — PlateA (port side) and PlateB (starboard side). When both are triggered within a short window, a trigger_device called VaultTrigger fires to open the treasure vault door. A hud_message_device called StatusHUD keeps the crew informed at every step.

Place These Devices in UEFN

The Verse Device

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }
using { /Fortnite.com/Characters }

# Localised message helpers
BothPlatesMsg<localizes>(S : string) : message = "{S}"
PlateAMsg<localizes>(S : string) : message = "{S}"
PlateBMsg<localizes>(S : string) : message = "{S}"
VaultOpenMsg<localizes>(S : string) : message = "{S}"

# dock_vault_logic — AND gate: both plates must fire before the vault opens.
# Place this Verse device on the island and wire the @editable fields.
dock_vault_logic := class(creative_device):

    # --- Editable device references ---
    @editable
    PlateA : trigger_device = trigger_device{}

    @editable
    PlateB : trigger_device = trigger_device{}

    @editable
    VaultTrigger : trigger_device = trigger_device{}

    @editable
    StatusHUD : hud_message_device = hud_message_device{}

    # --- Internal state ---
    var PlateATriggered : logic = false
    var PlateBTriggered : logic = false

    # --- Lifecycle ---
    OnBegin<override>()<suspends> : void =
        # Limit the vault to fire only once
        VaultTrigger.SetMaxTriggerCount(1)

        # Show a persistent hint at game start
        StatusHUD.SetDisplayTime(0.0)   # 0 = persistent
        StatusHUD.Show(BothPlatesMsg("Stand on BOTH dock plates to open the vault!"))

        # Subscribe to both plates
        PlateA.TriggeredEvent.Subscribe(OnPlateATriggered)
        PlateB.TriggeredEvent.Subscribe(OnPlateBTriggered)

    # --- Event handlers ---
    OnPlateATriggered(Agent : ?agent) : void =
        set PlateATriggered = true
        # Show per-agent feedback if we have a real agent, otherwise show global
        if (A := Agent?):
            StatusHUD.Show(A, PlateAMsg("Port plate locked in — waiting for starboard!"))
        else:
            StatusHUD.Show(PlateAMsg("Port plate locked in — waiting for starboard!"))
        CheckBothPlates(Agent)

    OnPlateBTriggered(Agent : ?agent) : void =
        set PlateBTriggered = true
        if (A := Agent?):
            StatusHUD.Show(A, PlateBMsg("Starboard plate locked in — waiting for port!"))
        else:
            StatusHUD.Show(PlateBMsg("Starboard plate locked in — waiting for port!"))
        CheckBothPlates(Agent)

    # --- AND gate check ---
    CheckBothPlates(Agent : ?agent) : void =
        # The AND: both flags must be true
        if (PlateATriggered = true and PlateBTriggered = true):
            # Fire the vault trigger — use the agent overload when we have one
            if (A := Agent?):
                VaultTrigger.Trigger(A)
            else:
                VaultTrigger.Trigger()
            StatusHUD.Show(VaultOpenMsg("VAULT OPEN! Grab the treasure, crew!"))
            # Reset flags so the puzzle can't re-fire (vault is already capped at 1)
            set PlateATriggered = false
            set PlateBTriggered = false

Line-by-Line Explanation

Common patterns

Pattern 1 — OR gate: captain's override OR crew plates

The captain can open the vault alone via a secret lever (OverridePlate), OR the two-crew AND gate succeeds. This uses or to combine two failable checks.

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }

OverrideMsg<localizes>(S : string) : message = "{S}"
CrewMsg<localizes>(S : string) : message = "{S}"

# OR gate: override plate alone is enough, OR both crew plates
dock_or_gate := class(creative_device):

    @editable
    OverridePlate : trigger_device = trigger_device{}

    @editable
    CrewPlateA : trigger_device = trigger_device{}

    @editable
    CrewPlateB : trigger_device = trigger_device{}

    @editable
    VaultTrigger : trigger_device = trigger_device{}

    @editable
    StatusHUD : hud_message_device = hud_message_device{}

    var OverrideReady : logic = false
    var CrewAReady : logic = false
    var CrewBReady : logic = false

    OnBegin<override>()<suspends> : void =
        VaultTrigger.SetMaxTriggerCount(1)
        OverridePlate.TriggeredEvent.Subscribe(OnOverride)
        CrewPlateA.TriggeredEvent.Subscribe(OnCrewA)
        CrewPlateB.TriggeredEvent.Subscribe(OnCrewB)

    OnOverride(Agent : ?agent) : void =
        set OverrideReady = true
        CheckOrGate(Agent)

    OnCrewA(Agent : ?agent) : void =
        set CrewAReady = true
        CheckOrGate(Agent)

    OnCrewB(Agent : ?agent) : void =
        set CrewBReady = true
        CheckOrGate(Agent)

    CheckOrGate(Agent : ?agent) : void =
        # OR gate: captain override alone, OR both crew plates
        if (OverrideReady = true or (CrewAReady = true and CrewBReady = true)):
            if (A := Agent?):
                VaultTrigger.Trigger(A)
                StatusHUD.Show(A, OverrideMsg("Vault breached! Well played, captain."))
            else:
                VaultTrigger.Trigger()
                StatusHUD.Show(CrewMsg("Vault open — crew effort wins the day!"))
            set OverrideReady = false
            set CrewAReady = false
            set CrewBReady = false

Pattern 2 — Querying trigger state with GetTriggerCountRemaining and SetResetDelay

After the vault fires, display how many uses remain on a secondary alarm trigger, and set a cooldown before it can fire again. This covers GetTriggerCountRemaining, GetMaxTriggerCount, and SetResetDelay.

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }

AlarmMsg<localizes>(S : string) : message = "{S}"

# Shows trigger stats and sets a reset delay on an alarm trigger
dock_alarm_stats := class(creative_device):

    @editable
    AlarmTrigger : trigger_device = trigger_device{}

    @editable
    StatusHUD : hud_message_device = hud_message_device{}

    OnBegin<override>()<suspends> : void =
        # Allow the alarm to fire up to 3 times, with a 5-second cooldown between fires
        AlarmTrigger.SetMaxTriggerCount(3)
        AlarmTrigger.SetResetDelay(5.0)

        AlarmTrigger.TriggeredEvent.Subscribe(OnAlarmFired)

    OnAlarmFired(Agent : ?agent) : void =
        MaxCount := AlarmTrigger.GetMaxTriggerCount()
        Remaining := AlarmTrigger.GetTriggerCountRemaining()
        ResetDelay := AlarmTrigger.GetResetDelay()
        # Build a status string from the live device values
        # (Remaining and MaxCount are int; ResetDelay is float)
        # Show a timed message — 4 seconds, then auto-hide
        StatusHUD.Show(AlarmMsg("Alarm fired! Cooldown active. Check the dock."), ?DisplayTime := 4.0)

Pattern 3 — ClearAllMessages and HideMessageEvent

When the round ends (simulated here by a reset trigger), clear every queued HUD message and subscribe to HideMessageEvent to log when a message disappears from any player's screen.

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }

ClearedMsg<localizes>(S : string) : message = "{S}"

# Clears HUD messages on a reset trigger and reacts to HideMessageEvent
dock_hud_cleanup := class(creative_device):

    @editable
    ResetTrigger : trigger_device = trigger_device{}

    @editable
    StatusHUD : hud_message_device = hud_message_device{}

    OnBegin<override>()<suspends> : void =
        ResetTrigger.TriggeredEvent.Subscribe(OnReset)
        StatusHUD.HideMessageEvent.Subscribe(OnMessageHidden)

    OnReset(Agent : ?agent) : void =
        # Wipe every queued message for all players
        StatusHUD.ClearAllMessages()
        # Re-enable the trigger so the reset can fire again
        ResetTrigger.Enable()

    OnMessageHidden(HideAgent : agent) : void =
        # Fires each time a message is hidden from a specific agent's screen
        # Show a brief confirmation only to that agent
        StatusHUD.Show(HideAgent, ClearedMsg("HUD cleared — new round incoming!"), ?DisplayTime := 2.0)

Gotchas

1. ?agent is NOT agent — always unwrap it

TriggeredEvent on trigger_device hands your handler a ?agent (optional agent). If you pass it directly to StatusHUD.Show(Agent, ...) the compiler rejects it — Show wants a plain agent. Unwrap first:

if (A := Agent?):
    StatusHUD.Show(A, MyMsg("Hello, pirate!"))
else:
    StatusHUD.Show(MyMsg("Hello, everyone!"))

2. message ≠ string — use a <localizes> function

Methods like SetText, Show(Message:message), and Show(Agent, Message:message) require a message value. You cannot pass a raw string literal or use a fictional StringToMessage. Declare a localizer at file scope:

MyText<localizes>(S : string) : message = "{S}"
// then call:
StatusHUD.SetText(MyText("Dock is clear!"))

3. and/or in if guards are failable combinators, not boolean operators

and fails the whole condition if either side fails. or short-circuits to the first success. This means:

# WRONG — logic variables are not failable by themselves:
if (PlateATriggered and PlateBTriggered):   # compile error

# CORRECT — compare to a concrete value:
if (PlateATriggered = true and PlateBTriggered = true):

4. SetMaxTriggerCount clamps to [0, 20]

Passing a value above 20 silently clamps to 20. Use 0 for unlimited. Always call GetMaxTriggerCount() after setting if you need to verify the clamped result.

5. int and float don't auto-convert

SetResetDelay takes a float; SetMaxTriggerCount takes an int. Passing 5 where 5.0 is expected (or vice-versa) is a compile error. Always match the literal type to the parameter type.

6. @editable fields MUST be declared inside the class body

A bare VaultTrigger.Trigger() at file scope with no class declaration fails with Unknown identifier. Every device reference must be an @editable field of a class(creative_device), and all logic must live in OnBegin or class-scope methods.