小编Mia*_*a.M的帖子

我这里有一个元组列表，我想dir..在每个元组的第一个元素上应用函数。我怎样才能做到这一点？在此先多谢！

[ ("grid", gridResponse),
("graph", graphResponse),
("image", graphImageResponse),
("timetable-image", timetableImageResponse x),
("graph-fb",toResponse ""),
("post-fb",toResponse ""),
("test", getEmail),
("test-post", postToFacebook),
("post", postResponse),
("draw", drawResponse),                  
("about", aboutResponse),
("privacy" ,privacyResponse),
("static", serveDirectory),
("course", retrieveCourse),
("all-courses", allCourses),
("graphs", queryGraphs),
("course-info", courseInfo),
("depts", deptList),
("timesearch",searchResponse),
("calendar",calendarResponse),
("get-json-data",getGraphJSON),
("loading",loadingResponse),
("save-json", saveGraphJSON)?

我们平时看到的=,<-,<=在Haskell.这些有什么区别？