{"id":305,"date":"2022-05-11T14:06:13","date_gmt":"2022-05-11T14:06:13","guid":{"rendered":"http:\/\/114.132.224.28\/?p=305"},"modified":"2022-05-11T14:06:13","modified_gmt":"2022-05-11T14:06:13","slug":"lesson3-first-class-functions","status":"publish","type":"post","link":"http:\/\/localhost\/2022\/05\/11\/lesson3-first-class-functions\/","title":{"rendered":"lesson3   First-Class Functions"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-5.png\" alt=\"\" class=\"wp-image-348\"\/><\/figure>\n\n\n\n<p>\u51fd\u6570\u5f0f\u7f16\u7a0b\u4e3b\u8981\u4f53\u73b0\u5728\uff0c1.\u907f\u514d\u6570\u636e\u53ef\u53d8 2.\u628a\u51fd\u6570\u4f5c\u4e3a\u503c\u4f7f\u7528\uff0c\u5b83\u53ef\u4ee5\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\uff0c\u4f5c\u4e3a\u503c\u8fd4\u56de\uff0c\u53ef\u4ee5\u8d4b\u503c\u7ed9\u5176\u4ed6\u53d8\u91cf<\/p>\n\n\n\n<p>\u51fd\u6570\u5f0f\u8bed\u8a00\u5728\u51fd\u6570\u7f16\u7a0b\u5b9e\u73b0\uff0c\u4e5f\u80fd\u5728\u5176\u4ed6\u7f16\u7a0b\u65b9\u5f0f\u5b9e\u73b0\u4ed6<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-6.png\" alt=\"\" class=\"wp-image-350\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-7.png\" alt=\"\" class=\"wp-image-351\"\/><\/figure>\n\n\n\n<p>\u51fd\u6570\u95ed\u5305\uff0c\u5728\u89e3\u51b3\u5982\u679c\u8fd9\u4e2a\u53d8\u91cf\u4e0d\u662f\u5c40\u90e8\u53d8\u91cf\uff0c\u4e5f\u4e0d\u662f\u53c2\u6570\uff0c\u8981\u600e\u4e48\u4f7f\u7528\u8fd9\u4e2a\u53d8\u91cf<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-8.png\" alt=\"\" class=\"wp-image-352\"\/><\/figure>\n\n\n\n<p>\u9ad8\u9636\u51fd\u6570\u7ecf\u5e38\u662f\u591a\u6001\u7684\uff0c\u4f46\u4e24\u53ea\u4e0d\u662f\u76f8\u4e92\u5fc5\u7136\u7684\u5173\u7cfb<\/p>\n\n\n\n<p><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-11.png\" alt=\"\" class=\"wp-image-355\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-9.png\" alt=\"\" class=\"wp-image-353\"\/><\/figure>\n\n\n\n<p>\u8c03\u7528\u95ed\u5305\u51fd\u6570\u5206\u4e3a\u4e24\u4e2a\u90e8\u5206\uff0c\u4e00\u90e8\u5206\u662f\u8fd9\u6bb5\u51fd\u6570\u7684\u4ee3\u7801\uff0c\u53e6\u4e00\u90e8\u5206\u662f\u4ed6\u7684\u4f5c\u7528\u57df<\/p>\n\n\n\n<p>\u8bcd\u6cd5\u4f5c\u7528\u57df\uff1a\u6839\u636e\u51fd\u6570\u5b9a\u4e49\u7684\u73af\u5883\u627e\u5230\u503c<\/p>\n\n\n\n<p>\u52a8\u6001\u4f5c\u7528\u57df\uff1a\u6839\u636e\u8c03\u7528\u6808\u7684\u73af\u5883\u627e\u5230\u503c\uff08e.g \u6355\u83b7\u5f02\u5e38\uff09<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-12.png\" alt=\"\" class=\"wp-image-356\" width=\"920\" height=\"590\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-13.png\" alt=\"\" class=\"wp-image-357\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-15.png\" alt=\"\" class=\"wp-image-359\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-14.png\" alt=\"\" class=\"wp-image-358\"\/><\/figure>\n\n\n\n<p><\/p>\n\n\n\n<p>ref\u7c7b\u578b ml\u7684data\u53ef\u53d8\u7c7b\u578b<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-16.png\" alt=\"\" class=\"wp-image-360\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-17.png\" alt=\"\" class=\"wp-image-361\"\/><\/figure>\n\n\n\n<p>x\u7684reference\u4e0d\u4f1a\u6539\u53d8\u53ea\u4f1a\u6539\u53d8reference\u91cc\u9762\u7684\u503c\uff0c\u8fd9\u70b9\u8ddfjs\u4e0d\u540c<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-27.png\" alt=\"\" class=\"wp-image-391\" width=\"304\" height=\"80\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-28.png\" alt=\"\" class=\"wp-image-392\"\/><\/figure>\n\n\n\n<p>\u5728js,a\u7684reference\u5c31\u88ab\u91cd\u65b0\u6307\u5411\u4e86\uff0cml\u5219\u662f\u6539\u53d8reference\u91cc\u9762\u7684\u5185\u5bb9<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-18.png\" alt=\"\" class=\"wp-image-365\"\/><\/figure>\n\n\n\n<p>callback,\u5229\u7528\u95ed\u5305\uff0c\u5f53\u56de\u8c03\u88ab\u8c03\u7528\u65f6\uff0c\u5185\u90e8\u6570\u636e\u4e0d\u9700\u8981\u4f53\u73b0\u5728\u51fd\u6570\u7c7b\u578b\u91cc\u9762\uff0ccallback\u5b9e\u73b0\u8005\u4e5f\u4e0d\u9700\u8981\u8003\u8651\u4f1a\u6709\u4ec0\u4e48\u7c7b\u578b\u7684\u5185\u90e8\u4e66\u6570\u636e<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-24.png\" alt=\"\" class=\"wp-image-381\"\/><\/figure>\n\n\n\n<p>\u62bd\u8c61\u6570\u636e\u7c7b\u578b\uff0c\u901a\u8fc7\u5b9a\u4e49\u4e00\u4e2a\u51fd\u6570\u96c6\u5408\u6765\u5b9e\u73b0\uff0c\u5728\u4e00\u4e2a\u95ed\u5305\u51fd\u6570\u91cc\u9762\uff0c\u5b9e\u73b0\u8fd9\u4e2a\u51fd\u6570\u96c6\u5408\uff0c\u8fd9\u4e2a\u79c1\u6709\u53d8\u91cf\u4e0d\u4f1a\u88ab\u5916\u754c\u8bbf\u95ee\uff0c\u6bcf\u6b21\u8fd4\u56de\u65b0\u7684S\uff0cS\u7684xs\u62ff\u5230\u7684\u662finsert\u8fc7\u540e\u7684xs<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>datatype set = S of { insert : int -&gt; set, member : int -&gt; bool, size : unit -&gt; int }<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>val empty_set =\n    let\n        fun make_set xs = (* xs is a \"private field\" in result *)\n            let (* contains a \"private method\" in result *)\n                fun contains i = List.exists (fn j =&gt; i=j) xs\n            in\n                S { insert = fn i =&gt; if contains i\n                                     then make_set xs\n                                     else make_set (i::xs),\n                    member = contains,\n                    size   = fn () =&gt; length xs\n                  }\n             end\n    in\n          make_set &#91;]\n    end<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>fun use_sets () =\n    let val S s1 = empty_set\n        val S s2 = (#insert s1) 34\n        val S s3 = (#insert s2) 34\n        val S s4 = #insert s3 19\n    in\n        if (#member s4) 42\n        then 99\n        else if (#member s4) 19\n        then 17 + (#size s3) ()\n        else 0\nend<\/code><\/pre>\n\n\n\n<p>\u6ca1\u6709\u95ed\u5305\u8981\u600e\u4e48\u5b9e\u73b0\u95ed\u5305\uff1a<\/p>\n\n\n\n<ul><li>\u5728Java\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u5b9e\u73b0\u4e00\u4e2a\u5185\u90e8class,\u5185\u90e8class\u7684method\u62ff\u5230\u9700\u8981\u95ed\u5305\u7684\u503c\uff0c\u95ed\u5305\u7684\u79c1\u6709\u6570\u636e\u9700\u8981\u662ffinal\u4e0d\u53ef\u53d8\u7c7b\u578b<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-19.png\" alt=\"\" class=\"wp-image-370\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/05\/image.png\" alt=\"\" class=\"wp-image-308\" width=\"920\" height=\"340\"\/><\/figure>\n\n\n\n<ul><li>\u5728C\u4e2d\uff0c\u6211\u4eec\u867d\u7136\u53ef\u4ee5\u4f20\u9012\u51fd\u6570\uff0c\u4f46\u662f\u51fd\u6570\u662f\u4e0d\u53ef\u4ee5\u5728\u51fd\u6570\u5185\u90e8\u5b9a\u4e49\uff0c\u51fd\u6570\u5fc5\u987b\u5728\u5b9a\u4e49\u5728\u6700\u524d\u9762\uff0c\u56e0\u4e3a\u4e0d\u5b58\u5728\u975e\u5c40\u90e8\u53d8\u91cf\uff08\u4e0d\u662f\u53c2\u6570\u548c\u5c40\u90e8\u53d8\u91cf\uff09\uff0c\u90a3\u53c2\u6570\u5c31\u9700\u8981\u9010\u5c42\u4f20\u9012\uff0c\u4e0d\u80fd\u5229\u7528\u5185\u90e8\u5d4c\u5957\u51fd\u6570\uff0c\u83b7\u5f97\u975e\u5c40\u90e8\u53d8\u91cf\uff0c\u9700\u8981\u52a8\u6001\u53bb\u4f20\u8fd9\u4e2aenv\u503c\uff08\u4e0a\u4e0b\u6587\uff09<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/05\/image-1.png\" alt=\"\" class=\"wp-image-309\"\/><\/figure>\n\n\n\n<p>\u800c\u5bf9\u4e8e\u6709\u95ed\u5305\u7684\u60c5\u51b5\uff0cml\u53ef\u4ee5\u4e0d\u53bb\u4f20\u9012\u8fd9\u4e2aenv\uff0c\u8fd9\u4e2a\u503c\u5728\u5b83\u5b9a\u4e49\u7684\u65f6\u5019\u5df2\u7ecf\u88ab\u7ed1\u5b9a<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/05\/image-3.png\" alt=\"\" class=\"wp-image-311\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/05\/image-2.png\" alt=\"\" class=\"wp-image-310\"\/><\/figure>\n\n\n\n<p>\u95ed\u5305\u597d\u5904\u5728\u4e8e\uff0c\u53ef\u4ee5\u5c06map\u5206\u79bb\uff0cmap\u7684\u5236\u5b9a\u8005\u77e5\u9053\u600e\u4e48\u53bb\u904d\u5386\u9012\u5f52\u6570\u636e\uff0cmap\u7684\u4f7f\u7528\u8005\u77e5\u9053\u600e\u4e48\u5904\u7406\u6570\u636e\uff0c\u800c\u50cfC\u7248\u672c\u7684\u5b9e\u73b0\u5f53\u4e2d\uff0cmap\u7684\u5236\u5b9a\u8005\u5c31\u5fc5\u987b\u5c06env\u4f20\u9012\uff0c\u800c\u8fd9\u4e2aenv\u5bf9\u4e8e\u5236\u5b9a\u8005\u6765\u8bf4\u662f\u4e0d\u5fc5\u8981\uff0c\u4f46\u662f\u6ca1\u6709\u8fd9\u4e2aenv\uff0c\u4f7f\u7528\u8005\u5c31\u65e0\u6cd5\u53bb\u62ff\u5230\u8fd9\u4e2a\u6570\u636e\uff0c\u56e0\u4e3a\u8fd9\u4e2a\u51fd\u6570\u7684\u8c03\u7528\u662f\u5728\u5236\u5b9a\u8005\u5f53\u4e2d\u7684<\/p>\n\n\n\n<p><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2022\/06\/image-25.png\" alt=\"\" class=\"wp-image-385\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>\u51fd\u6570\u5f0f\u7f16\u7a0b\u4e3b\u8981\u4f53\u73b0\u5728\uff0c1.\u907f\u514d\u6570\u636e\u53ef\u53d8 2.\u628a\u51fd\u6570 &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"_links":{"self":[{"href":"http:\/\/localhost\/wp-json\/wp\/v2\/posts\/305"}],"collection":[{"href":"http:\/\/localhost\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/localhost\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/localhost\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/localhost\/wp-json\/wp\/v2\/comments?post=305"}],"version-history":[{"count":0,"href":"http:\/\/localhost\/wp-json\/wp\/v2\/posts\/305\/revisions"}],"wp:attachment":[{"href":"http:\/\/localhost\/wp-json\/wp\/v2\/media?parent=305"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/localhost\/wp-json\/wp\/v2\/categories?post=305"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/localhost\/wp-json\/wp\/v2\/tags?post=305"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}