feat: add molang package

1. upgrade bukkit chat
2. fix config update error

Signed-off-by: MiaoWoo <admin@yumc.pw>

packages/molang/src/parser/expression.ts

@@ -0,0 +1,57 @@
+/**
+ * Interface that describes an AST Expression
+ */
+export interface IExpression {
+	readonly type: string
+	readonly isReturn?: boolean
+	readonly isBreak?: boolean
+	readonly isContinue?: boolean
+	readonly allExpressions: IExpression[]
+
+	setFunctionCall?: (value: boolean) => void
+	setPointer?: (value: unknown) => void
+	setExpressionAt(index: number, expr: IExpression): void
+	eval(): unknown
+	isStatic(): boolean
+	walk(cb: TIterateCallback): IExpression
+	iterate(cb: TIterateCallback, visited: Set<IExpression>): void
+}
+
+export abstract class Expression implements IExpression {
+	public abstract readonly type: string
+
+	abstract eval(): unknown
+	abstract isStatic(): boolean
+
+	toString() {
+		return `${this.eval()}`
+	}
+
+	abstract allExpressions: IExpression[]
+	abstract setExpressionAt(index: number, expr: IExpression): void
+
+	walk(cb: TIterateCallback, visited = new Set<IExpression>()): IExpression {
+		let expr = cb(this) ?? this
+
+		expr.iterate(cb, visited)
+
+		return expr
+	}
+	iterate(cb: TIterateCallback, visited: Set<IExpression>) {
+		for (let i = 0; i < this.allExpressions.length; i++) {
+			const originalExpr = this.allExpressions[i]
+			if (visited.has(originalExpr)) continue
+			else visited.add(originalExpr)
+
+			const expr = cb(originalExpr) ?? originalExpr
+
+			if (expr !== originalExpr && visited.has(expr)) continue
+			else visited.add(expr)
+
+			this.setExpressionAt(i, expr)
+			expr.iterate(cb, visited)
+		}
+	}
+}
+
+export type TIterateCallback = (expr: IExpression) => IExpression | undefined