Gate#

The Gate node is a flow control node that allows you to conditionally allow or block the flow of execution in your spell based on external triggers. It acts like a gate or valve, letting the flow pass through when opened and blocking it when closed.

Inputs#

• flow (required): The main flow input that the Gate will control.
• open: A flow signal to open the Gate and allow the main flow to pass through.
• close: A flow signal to close the Gate and block the main flow.
• toggle: A flow signal to toggle the Gate between open and closed states.
• startClosed (boolean, default: false): If true, the Gate will start in the closed state. Otherwise, it starts open.

Outputs#

• flow: The controlled flow output. Emits the main flow input when the Gate is open, and blocks it when closed.

Usage#

1. Connect your main execution flow to the Gate's flow input.
2. (Optional) Connect flow signals to the open, close, and/or toggle inputs to control the Gate's state.
3. Set the startClosed option if you want the Gate to initially block the flow.
4. Connect the Gate's flow output to the next node(s) in your spell.

When the Gate receives a signal on its open input, it will allow the main flow to pass through to the output. A signal on close will block the flow. The toggle input switches the Gate between open and closed states each time it receives a signal.

Example#

Suppose you have a spell that needs to conditionally send an HTTP request based on some external condition. You can use a Gate node to control the flow:

Trigger --> Gate --> HTTP Request
              ^
              |
          Condition

The Trigger node starts the flow, which is connected to the Gate's flow input. The Condition node (e.g. a Button or Delay node) is connected to the Gate's toggle input.

• When the Condition node fires, it toggles the Gate open, allowing the flow to continue to the HTTP Request node.
• If the Condition doesn't fire, the Gate remains closed and blocks the flow, preventing the HTTP request.

Best Practices#

• Use Gates judiciously to control flow and resources. Too many Gates can make a spell hard to follow.
• Clearly label Gate nodes and their control inputs (open, close, toggle) to make the flow logic easy to understand at a glance.
• Consider using a single toggle input instead of separate open and close where appropriate to simplify the spell graph.

Common Issues#

• Forgetting to set startClosed when you need the Gate to block the initial flow.
• Connecting control signals to the wrong Gate inputs.
• Creating infinite loops by connecting a Gate's output back to its own control inputs incorrectly.

With careful use, the Gate node provides a powerful way to dynamically control the execution flow of your spells based on events and conditions.