add some sifter helpers

Author: vytdev

src/sifter/index.ts

@@ -3,7 +3,11 @@
  * This plugin is part of the bricklib project.
  */
 
+import { Player } from '@minecraft/server';
 import * as bricklib from '../bricklib/index.js';
+import { parseVerb } from './parser.js';
+import { ParseContext, ParseResult } from './state.js';
+import type { CmdVerb } from './types.ts';
 
 export * from './parser.js';
 export * from './state.js';
@@ -13,3 +17,38 @@ export type * from './types.ts';
 bricklib.plugin.newPlugin('sifter', () => {
   /* no-op */
 });
+
+
+/**
+ * Parse a command definition.
+ * @param cmdDef The parsing rules.
+ * @param args The tokenized arguments.
+ * @returns The parsing result.
+ */
+export function parseCommand(cmdDef: CmdVerb, args: string[]): ParseResult
+{
+  const ctx = new ParseContext(args);
+  ctx.consumeToken();     /* skip the first arg (name of the cmd) */
+  const res = new ParseResult();
+  parseVerb(ctx, res, cmdDef);
+  return res;
+}
+
+/**
+ * Register a custom command using sifter as its parser.
+ * @param mgr The bricklib custom command manager.
+ * @param cmdDef The command parsing definition.
+ * @param fn The callback function.
+ * @returns The registered names for the cmd.
+ */
+export function registerCommand(
+    mgr: bricklib.command.CommandManager, cmdDef: CmdVerb,
+    fn: (args: ParseResult, src: Player) => number): string[]
+{
+  let names = [cmdDef.name];
+  if (cmdDef.aliases)
+    names = names.concat(cmdDef.aliases);
+  mgr.registerCommand(names,
+      (src, args) => fn(parseCommand(cmdDef, args), src));
+  return names;
+}