81 lines
No EOL
2.7 KiB
Markdown
81 lines
No EOL
2.7 KiB
Markdown
## Limitations & Bugs
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- argument's can't require specific permissions.
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- errors are always formatted using the RootLiteral's MessageStyle
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## Design
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Commands are trees of Literals.
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Literals can have arguments.
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Literals can also have Executors.
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arguments can be optional by giving them a default value.
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arguments can have suggestions.
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`/feed <user>`:
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- feed is the root literal
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- `<user>` is an argument: it's value is a User Object
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To allow the use of `/feed` without giving a user's name, i.e. to make the argument optional, we need to assign the
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user-argument a default value.
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## An example command
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Let's say we want to make a command that allows seeing how many coins another User has.
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If we don't specify a user, it should instead show the coins the sender has.
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## As a tree
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Visualized as a tree, we have a Node/Literal `coins` with an alias `balance` with an optional argument called `user`.
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To make an argument optional, it must have a default value.
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```text
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literal:coins/balance
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- has argument:user
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- has executor:getCoins
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```
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## As code
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```java
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/**
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* Show the amount coins a user has.
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* If no user is given, it should show the amount the sender of the command has.
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*/
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@NoArgsConstructor(access = AccessLevel.NONE)
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public class CoinsCommand {
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@Getter
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private final Literal<User> rootLiteral;
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private final CommandArgumentSpec<User, User> userArg;
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public CoinsCommand() {
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userArg = CommandArgumentSpec.builder("user", new UserArgumentType<User>())
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.withRequirement(p -> !p.hasPermission("economy.immune.getcoins"),
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"you can't see that player's balance")
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.withDefaultValue(CommandContext::getSender)
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.build();
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rootLiteral = Literal.<User>builder("coins", "balance")
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.withStyle(MessageStyle.PLAIN)
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.withPermission("economy.command.coins")
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.withArgument(userArg)
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.withSyncExecutor(this::getCoins)
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.build();
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}
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private Result<Object, String> getCoins(CommandContext<User> ctx) {
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var player = ctx.getArg(userArg);
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ctx.getSender().sendMessage(player.getName() + " has " + player.getCoins() + " coins");
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return Results.success(new Object());
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}
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}
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```
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If we wanted to report an error, we could do for example `return Results.failure("That user doesn't exist")`.
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However, if we have a smart UserArgumentType, it automatically makes sure that the user exists.
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Additionally, we can also a Requirement in the CommandArgumentSpec.
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The registration of the command is platform-dependant. Typically, a class called CommandAPI can be used.
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```java
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CommandAPI api = new CommandAPI();
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register(new CoinsCommand().getRootLiteral());
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``` |