我试图验证一个目录的存在,这样我就可以将它添加到一个有效目录的列表中,但是我得到了与类型不匹配有关的错误。else fpsMain.hs:141:28: error: Expected type: [Bool]* In a stmt of a 'do' block: direx <- doesPathExist (show newp)
type 'Future<bool>' is not a subtype of type 'bool' in type cast 以下是导致错误的源代码: Future<bool> fetchCoursesif (courses.length == 0) { } else { }..
boolhasCourses = fetchCourses()