Module valence_command::graph

Command graph implementation

This is the core of the command system. It is a graph of CommandNodes that are connected by the CommandEdgeType. The graph is used to determine what command to run when a command is entered. The graph is also used to generate the command tree that is sent to the client.

The graph is a directed graph with 3 types of nodes:

• Root node ([NodeData::Root]) - This is the root of the graph. It is used to connect all the other nodes to the graph. It is always present and there should only be one.
• Literal node ([NodeData::Literal]) - This is a literal part of a command. It is a string that must be matched exactly by the client to trigger the validity of the node. For example, the command /teleport would have a literal node with the name teleport which is a child of the root node.
• Argument node ([NodeData::Argument]) - This is a node that represents an argument in a command. It is a string that is matched by the client and checked by the server. For example, the command /teleport 0 0 0 would have 1 argument node with the name “destination:location” and the parser [Parser::Vec3] which is a child of the literal node with the name teleport.

and 2 types of edges:

• Child edge (CommandEdgeType::Child) - This is an edge that connects a parent node to a child node. It is used to determine what nodes are valid children of a parent node. for example, the literal node with the name teleport would have a child edge to the argument node with the name “destination:location”. This means that the argument node is a valid child of the literal node.
• Redirect edge (CommandEdgeType::Redirect) - This edge is special. It is used to redirect the client to another node. For example, the literal node with the name tp would have a Redirect edge to the literal node with the name teleport. This means that if the client enters the command /tp the server will redirect the client to the literal node with the name teleport. Making the command /tp functionally equivalent to /teleport.

Cool Example Graph For Possible Implementation Of Teleport Command (made with graphviz)

                                              ┌────────────────────────────────┐
                                              │              Root              │ ─┐
                                              └────────────────────────────────┘  │
                                                │                                 │
                                                │ Child                           │
                                                ▼                                 │
                                              ┌────────────────────────────────┐  │
                                              │          Literal: tp           │  │
                                              └────────────────────────────────┘  │
                                                │                                 │
                                                │ Redirect                        │ Child
                                                ▼                                 ▼
┌──────────────────────────────────┐  Child   ┌──────────────────────────────────────────────────────────────────────────────┐
│  Argument: <destination:entity>  │ ◀─────── │                              Literal: teleport                               │
└──────────────────────────────────┘          └──────────────────────────────────────────────────────────────────────────────┘
                                                │                                           │
                                                │ Child                                     │ Child
                                                ▼                                           ▼
┌──────────────────────────────────┐  Child   ┌────────────────────────────────┐          ┌──────────────────────────────────┐
│ Argument: <destination:location> │ ◀─────── │   Argument: <target:entity>    │          │ Argument: <destination:location> │
└──────────────────────────────────┘          └────────────────────────────────┘          └──────────────────────────────────┘
                                                │
                                                │ Child
                                                ▼
                                              ┌────────────────────────────────┐
                                              │ Argument: <destination:entity> │
                                              └────────────────────────────────┘

If you want a cool graph of your own command graph you can use the display trait on the CommandGraph struct. Then you can use a tool like Graphviz Online to look at the graph.

Structs

• CommandGraph
  This struct is used to store the command graph. (see module level docs for more info)
• CommandGraphBuilder
  Ergonomic builder pattern for adding executables, literals and arguments to a command graph. See the derive macro for a more ergonomic way of doing this for a basic command with an enum or struct.
• CommandNode
  Data for the nodes in the graph (see module level docs for more info)

Enums

• CommandEdgeType