我正在學(xué)習(xí) golang 源代碼并陷入延遲函數(shù)執(zhí)行順序。我有兩個(gè)文件：一個(gè)定義端點(diǎn)的行為，另一個(gè)用于測(cè)試。我刪除了一些與我的問題無(wú)關(guān)的代碼以減少閱讀的行數(shù)。端點(diǎn)定義文件// Endpoint is the fundamental building block of servers and clients.// It represents a single RPC method.type Endpoint func(ctx context.Context, request interface{}) (response interface{}, err error)// Middleware is a chainable behavior modifier for endpoints.type Middleware func(Endpoint) Endpoint// Chain is a helper function for composing middlewares. Requests will// traverse them in the order they're declared. That is, the first middleware// is treated as the outermost middleware.func Chain(outer Middleware, others ...Middleware) Middleware {    return func(next Endpoint) Endpoint {        for i := len(others) - 1; i >= 0; i-- { // reverse            next = others[i](next)        }        return outer(next)    }}測(cè)試文件包含打印的步驟。func ExampleChain() {    e := endpoint.Chain(        annotate("first"),        annotate("second"),        annotate("third"),    )(myEndpoint)    if _, err := e(ctx, req); err != nil {        panic(err)    }    // Output:    // first pre    // second pre    // third pre    // my endpoint!    // third post    // second post    // first post}var (    ctx = context.Background()    req = struct{}{})據(jù)我了解，這三個(gè)annotate方法應(yīng)該先執(zhí)行，然后endpoint.Chain方法，myEndpoint最后執(zhí)行。此外，由于pre首先打印，并且當(dāng)函數(shù)返回“post”時(shí)，應(yīng)該按照defergo doc 中的說(shuō)明進(jìn)行操作： A "defer" statement invokes a function whose execution is deferred to the moment the surrounding function returns, either because the surrounding function executed a return statement, reached the end of its function body, or because the corresponding goroutine is panicking.所以我期望看到的是    // Output:    // first pre    // first post    // second pre    // second post    // third pre    // third post    // my endpoint!簡(jiǎn)而言之，我的問題是：為什么first pre后面不跟first post，一樣second third。s的順序post顛倒了。endpoint.Chain反向執(zhí)行返回值列表但annotate首先annotate評(píng)估方法對(duì)嗎？不是說(shuō)，pres 被打印，這意味著首先執(zhí)行內(nèi)部函數(shù)