Question

我在Clojure中有一个函数，我想在发生异常时返回true，就像下面的代码一样;

    (try
        (code)
    (catch Exception e (= 1 1)))

然而，上述方法给出了以下错误：

ClassCastException java.lang.Boolean不能强制转换为clojure.lang.IFn signal.message / read？（message.clj：12）

只有在放置函数时才有效：

angular.module('starter.controllers', [])

.controller('SearchCtrl', function ($scope, $http, $ionicLoading) {

$scope.results = [];

$scope.search = function () {
    $ionicLoading.show({ template: 'Loading...' });

    $http.get('https://www.googleapis.com/youtube/v3/search?part=snippet&q=' + $scope.searchtext + '&key=').
        then(function (data) {

            var searchResults = data

            angular.forEach(searchResults.data.items, function (val, i) {

                $http.get('https://www.googleapis.com/youtube/v3/videos?part=snippet,contentDetails&id=' + val.id.videoId + '&key=').
                then(function (data) {

                    var durationResults = data
                    var duration = durationResults.data.items[0].contentDetails.duration.replace("PT", "").replace("H", ":").replace("M", ":").replace("S", "")

                    $scope.results.push({ thumbnail: val.snippet.thumbnails.medium.url, title: val.snippet.title, channel: durationResults.data.items[0].snippet.channelTitle, description: val.snippet.description, duration: duration })
                });

            });
        });

    $ionicLoading.hide();
};

})


<ion-view title="Search for Music">

    <ion-content scroll="true" class="has-header padding">

        <form ng-submit="search()" class="list list-inset">
            <label class="item item-input">
                <i class="icon ion-search placeholder-icon"></i>
                <input type="search" name="searchtext" ng-model="searchtext" placeholder="Search">
            </label>
        </form>

        <ion-list>
            <ion-item ui-sref="home" ng-repeat="result in results" class="item item-thumbnail-left">
                <img src="{{result.thumbnail}}">
                <h2>{{result.title}}</h2>
                <strong>{{result.channel}}</strong>
                <p>{{result.description}}</p>
                <p>Duration: {{result.duration}}</p>
            </ion-item>
        </ion-list>

    </ion-content>
</ion-view>

任何方式返回Clojure catch的值？

Answer 1

使用：

测试catch

(try
  (throw (RuntimeException.))
  (catch Exception e true)))

运行此代码将返回true。

Answer 2

你在问题中所写的内容是完全正确的：如果(code)抛出异常，那么try / catch as write会返回true。问题出在其他地方：这个try / catch周围的代码有太多括号，或者你粘贴的代码与你正在运行的实际代码不匹配。

如何在Clojure try / catch上返回一个值

2 个答案: