refactor(evaluate): remove unused V1 format code and simplify evaluator

Removed isV2Format detection function and legacy buildEvaluatorFunctionBody since V2 format is now the default. This simplifies the codebase and removes dead code paths.

Author: codehz

src/evaluate.ts

@@ -5,13 +5,6 @@ import type { BranchNode, CompiledData, CompiledExpression, ControlFlowNode, Jum
  */
 const evaluatorCache = new Map<string, (values: unknown[]) => unknown>();
 
-/**
- * 检测编译数据是否包含控制流节点（V2 格式）
- */
-function isV2Format(expressions: CompiledExpression[]): boolean {
-  return expressions.some((expr) => Array.isArray(expr));
-}
-
 /**
  * 分析并验证控制流结构，将 br/jmp/phi 翻译为 if-else 语句
  *
@@ -198,10 +191,8 @@ export function evaluate<TResult = unknown>(data: CompiledData, values: Record<s
   let evaluator = evaluatorCache.get(cacheKey);
 
   if (!evaluator) {
-    // 根据格式选择合适的函数体构造器
-    const functionBody = isV2Format(expressions)
-      ? buildEvaluatorFunctionBodyV2(expressions, variableNames.length)
-      : buildEvaluatorFunctionBody(expressions as string[], variableNames.length);
+    // 默认使用 V2 格式的函数体构造器
+    const functionBody = buildEvaluatorFunctionBodyV2(expressions, variableNames.length);
     // eslint-disable-next-line @typescript-eslint/no-implied-eval
     evaluator = new Function("$values", functionBody) as (values: unknown[]) => unknown;
     evaluatorCache.set(cacheKey, evaluator);
@@ -216,34 +207,6 @@ export function evaluate<TResult = unknown>(data: CompiledData, values: Record<s
   }
 }
 
-/**
- * 构造求值函数体
- *
- * @param expressions - 表达式列表
- * @param variableCount - 变量数量
- * @returns 函数体字符串
- *
- * @example
- * ```ts
- * buildEvaluatorFunctionBody(["$0+$1", "$2*2"], 2)
- * // 返回执行 $0+$1 并存储到 $values[2]，然后执行 $2*2 的函数体
- * ```
- */
-function buildEvaluatorFunctionBody(expressions: string[], variableCount: number): string {
-  if (expressions.length === 0) throw new Error("No expressions to evaluate");
-
-  const lines = [
-    ...Array.from({ length: variableCount }, (_, i) => `const $${i} = $values[${i}];`),
-    ...expressions.map((expr, i) => {
-      const idx = variableCount + i;
-      return `const $${idx} = ${expr}; $values[${idx}] = $${idx};`;
-    }),
-    `return $values[$values.length - 1];`,
-  ];
-
-  return lines.join("\n");
-}
-
 /**
  * 构造带控制流支持的求值函数体（V2 格式）
  *