{"id":249,"date":"2018-12-10T23:59:48","date_gmt":"2018-12-10T15:59:48","guid":{"rendered":"https:\/\/wp.winter-weng.cc\/work\/?p=249"},"modified":"2018-12-10T23:59:48","modified_gmt":"2018-12-10T15:59:48","slug":"ch-1-%e4%bd%95%e8%ac%82%e7%af%84%e7%96%87","status":"publish","type":"post","link":"https:\/\/wp.winter-weng.cc\/work\/?p=249","title":{"rendered":"Ch. 1 \u4f55\u8b02\u7bc4\u7587"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_75 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"\u986f\u793a\/\u96b1\u85cf\u5167\u5bb9\u76ee\u9304\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#%E7%B7%A8%E8%AD%AF%E5%99%A8%E7%90%86%E8%AB%96\" >\u7de8\u8b6f\u5668\u7406\u8ad6<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#%E7%B7%A8%E8%AD%AF%E4%B8%89%E5%A4%A7%E6%AD%A5%E9%A9%9F\" >\u7de8\u8b6f\u4e09\u5927\u6b65\u9a5f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#%E4%BA%86%E8%A7%A3%E7%AF%84%E7%96%87\" >\u4e86\u89e3\u7bc4\u7587<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#%E5%8D%A1%E5%8F%B8\" >\u5361\u53f8<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#%E5%89%8D%E5%BE%8C%E5%BE%80%E8%BF%94\" >\u524d\u5f8c\u5f80\u8fd4<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#Compiler_%E8%AA%AA%E8%A9%B1%E4%BA%86\" >Compiler \u8aaa\u8a71\u4e86<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#%E5%B0%8F%E6%B8%AC%E9%A9%97\" >\u5c0f\u6e2c\u9a57<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#%E5%B7%A2%E7%8B%80%E7%AF%84%E7%96%87\" >\u5de2\u72c0\u7bc4\u7587<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#%E9%8C%AF%E8%AA%A4\" >\u932f\u8aa4<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/wp.winter-weng.cc\/work\/?p=249\/#%E8%A4%87%E7%BF%92\" >\u8907\u7fd2<\/a><\/li><\/ul><\/nav><\/div>\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E7%B7%A8%E8%AD%AF%E5%99%A8%E7%90%86%E8%AB%96\"><\/span><strong>\u7de8\u8b6f\u5668\u7406\u8ad6<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E7%B7%A8%E8%AD%AF%E4%B8%89%E5%A4%A7%E6%AD%A5%E9%A9%9F\"><\/span>\u7de8\u8b6f\u4e09\u5927\u6b65\u9a5f<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<ul class=\"wp-block-list\"><li>Tokenizing (\u8a9e\u6cd5\u57fa\u672c\u55ae\u5143\u5316) \u8207 Lexing (\u8a9e\u5f59\u5206\u6790)\u5c07\u4e00\u4e32\u5b57\u5143\u62c6\u89e3\u6210\u6709\u610f\u7fa9\u7684\u7d44\u584a (Tokens)\uff0c\u4f8b\u5982\u5c07 <code>var a = 2;<\/code> \u62c6\u89e3\u70ba var\u3001a\u3001=\u30012\u3001;<\/li><li>Parsing (\u5256\u6790)\u5c07 Token \u7d44\u6210\u6a39\u72c0\u7d50\u69cb (AST\uff0cAbstract Syntax Tree\uff0c\u62bd\u8c61\u8a9e\u6cd5\u6a39)\u3002<\/li><li><\/li><\/ul>\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img decoding=\"async\" src=\"https:\/\/rukiawinter-wordpress.s3.ap-northeast-1.amazonaws.com\/wp-content\/uploads\/sites\/2\/2018\/12\/ast.png\" alt=\"\" class=\"wp-image-251\" \/><\/figure><\/div>\n\n\n<ul class=\"wp-block-list\"><li>Code-Generation (\u7522\u751f\u76ee\u7684\u7a0b\u5f0f\u78bc)\u5c07 AST \u8f49\u70ba\u53ef\u57f7\u884c\u7684\u7a0b\u5f0f\u78bc\uff0c\u4e26\u505a\u7a0b\u5f0f\u7684\u6700\u4f73\u5316\u3002<\/li><\/ul>\n\n\n<hr class=\"wp-block-separator\" \/>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E4%BA%86%E8%A7%A3%E7%AF%84%E7%96%87\"><\/span><strong>\u4e86\u89e3\u7bc4\u7587<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E5%8D%A1%E5%8F%B8\"><\/span>\u5361\u53f8<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<ul class=\"wp-block-list\"><li>\nEngine\n\u8ca0\u8cac\u6574\u500b\u7de8\u8b6f\u904e\u7a0b\u4ee5\u53ca\u7a0b\u5f0f\u78bc\u57f7\u884c\u3002\n<\/li><li>\nCompiler\n\u505a\u9ede\u9ad2\u6d3b\uff0c\u8ca0\u8cac\u8655\u7406\u7de8\u8b6f\u7684\u4e09\u500b\u6b65\u9a5f\u3002\n<\/li><li>\nScope\n\u8ca0\u8cac\u6536\u96c6\u8207\u7dad\u8b77\u5df2\u5ba3\u544a\u7684\u8b8a\u6578\uff0c\u4e26\u898f\u7bc4\u5c0d\u65bc\u76ee\u524d\u6b63\u5728\u57f7\u884c\u7684\u7a0b\u5f0f\u78bc\u4f86\u8aaa\uff0c\u662f\u5426\u53ef\u4ee5\u53d6\u7528\u3002\n<\/li><\/ul>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E5%89%8D%E5%BE%8C%E5%BE%80%E8%BF%94\"><\/span>\u524d\u5f8c\u5f80\u8fd4<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"true\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">var a = 2;<\/pre>\n\n\n<ol class=\"wp-block-list\"><li>\u7de8\u8b6f\u6642\uff1aCompiler \u6703\u62c6\u89e3\u4e26\u89e3\u6790\u6210 AST\uff0c\u4f46\u5728\u7522\u751f\u7a0b\u5f0f\u78bc\u6642\uff0c\u6703\u5148\u8a62\u554f Scope \u662f\u5426\u5df2\u5b58\u5728 a \u9019\u500b\u8b8a\u6578\uff0c\u82e5\u6c92\u6709\uff0c\u5247\u8acb\u5b83\u65b0\u589e\u4e00\u500b\u3002<\/li><li>\u57f7\u884c\u6642\uff1aEngine \u6703\u8a62\u554f Scope \u662f\u5426\u6709 a \u53ef\u4ee5\u53d6\u7528\uff0c\u5982\u679c\u6c92\u6709\u6703\u4f9d\u5e8f\u5f80\u5916\u627e\uff0c\u6700\u5f8c\u82e5\u6c92\u6709\u627e\u5230\uff0c\u5c31\u6703\u5927\u53eb\u51fa\u932f\u4e86\u3002<\/li><\/ol>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Compiler_%E8%AA%AA%E8%A9%B1%E4%BA%86\"><\/span>Compiler \u8aaa\u8a71\u4e86<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<p>\u67e5\u627e\u8b8a\u6578\u53ef\u4ee5\u5206\u70ba\u5169\u985e\uff1a<\/p>\n\n\n<ul class=\"wp-block-list\"><li>LHS\uff1a\u627e\u5230\u8b8a\u6578\uff0c\u4f5c\u70ba\u6307\u5b9a\u7684\u76ee\u6a19 (e.g. <code>a = 2<\/code>)\u3002<\/li><li>RHS\uff1a\u53d6\u56de\u4e00\u500b\u503c (e.g. <code>console.log(a)<\/code> \u4e2d\u7684 a \u8207 console \u672c\u8eab)\u3002<\/li><\/ul>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E5%B0%8F%E6%B8%AC%E9%A9%97\"><\/span>\u5c0f\u6e2c\u9a57<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"true\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">function foo(a) {\n\tvar b = a;\n\t\treturn a + b;\n}\nvar c = foo(2);<\/pre>\n\n\n<p>LHS\uff1a<\/p>\n\n\n<ol class=\"wp-block-list\"><li>c =<\/li><li>\u96b1\u542b\u7684 a = 2<\/li><li>b =<\/li><\/ol>\n\n\n<p>RHS\uff1a<\/p>\n\n\n<ol class=\"wp-block-list\"><li>foo<\/li><li>= a<\/li><li>a<\/li><li>b<\/li><\/ol>\n\n\n<hr class=\"wp-block-separator\" \/>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E5%B7%A2%E7%8B%80%E7%AF%84%E7%96%87\"><\/span><strong>\u5de2\u72c0\u7bc4\u7587<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<p>\u7bc4\u7587\u53ef\u4ee5\u9472\u5d4c\u3002\u5728\u76ee\u524d\u57f7\u884c\u7684\u7bc4\u7587\u627e\u4e0d\u5230\u8b8a\u6578\u7684\u6642\u5019\uff0cEngine \u6703\u5f80\u5916\u5c64\u641c\u5c0b\uff0c\u76f4\u5230\u627e\u5230\uff0c\u6216\u662f\u9054\u5230\u5168\u57df\u70ba\u6b62\u3002<\/p>\n\n\n<p style=\"background-color:#fff8e3\" class=\"has-background\">\u5728\u700f\u89bd\u5668\u4e2d\uff0c\u5168\u57df\u5c31\u662f window \u7269\u4ef6\u3002window \u662f\u4e16\u754c\u7684\u521d\u59cb (\u7121\u8aa4)\u3002<\/p>\n\n\n<hr class=\"wp-block-separator\" \/>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E9%8C%AF%E8%AA%A4\"><\/span><strong>\u932f\u8aa4<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<p>LHS \u8207 RHS \u67e5\u627e\u6703\u5e36\u4f86\u4e0d\u540c\u7684\u932f\u8aa4\u3002<\/p>\n\n\n<p>ReferenceError\uff1a<\/p>\n\n\n<ul class=\"wp-block-list\"><li>RHS \u67e5\u627e\u8b8a\u6578\u5931\u6557\u6642\u3002<\/li><li>LHS \u67e5\u627e\u5931\u6557\u6642\uff0c\u5728\u56b4\u683c\u6a21\u5f0f (Strict Mode) \u4e0b\u6703\u62cb\u51fa ReferenceError\uff0c\u5426\u5247\uff0c\u6703\u5728\u5168\u57df\u7bc4\u570d\u4e2d\u81ea\u52d5\u65b0\u589e\u8b8a\u6578\u3002<\/li><\/ul>\n\n\n<p>TypeError\uff1a<\/p>\n\n\n<ul class=\"wp-block-list\"><li>RHS\uff1a\u5c07\u4e0d\u662f\u51fd\u5f0f\u7684\u8b8a\u6578\u7576\u6210\u51fd\u5f0f\u4f86\u5ba3\u544a\uff0c\u6216\u662f\u5728 null \u6216 undefined \u7684\u8b8a\u6578\u4e0b\u53c3\u8003\u4e00\u500b\u5c6c\u6027 (e.g. <code>var a; a.b<\/code>)\u3002<\/li><li>LHS\uff1a\u91cd\u8907\u5ba3\u544a const \u8b8a\u6578\u3002<\/li><\/ul>\n\n\n<hr class=\"wp-block-separator\" \/>\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E8%A4%87%E7%BF%92\"><\/span><strong>\u8907\u7fd2<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n<ul class=\"wp-block-list\"><li>\u89e3\u91cb Scope \u662f\u4ec0\u9ebc\u3002<\/li><li>\u89e3\u91cb LHS \u8207 RHS\u3002<\/li><li>\u63cf\u8ff0\u5f15\u64ce\u8207\u7de8\u8b6f\u5668\u5728\u9047\u5230 <code>var a = 2<\/code> \u6642\uff0c\u6703\u505a\u54ea\u4e9b\u52d5\u4f5c\u3002<\/li><li>LHS \u8207 RHS \u67e5\u627e\u6642\u5982\u679c\u627e\u4e0d\u5230\u6703\u767c\u751f\u4ec0\u9ebc\u4e8b\uff1f<\/li><li>\u63cf\u8ff0\u67e5\u627e\u5931\u6557\u6642\u53ef\u80fd\u7522\u751f\u7684\u932f\u8aa4\u3002<\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\u7de8\u8b6f\u5668\u7406\u8ad6 \u7de8\u8b6f\u4e09\u5927\u6b65\u9a5f Tokenizing (&hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"pgc_sgb_lightbox_settings":"","footnotes":""},"categories":[13,12],"tags":[21],"class_list":["post-249","post","type-post","status-publish","format-standard","hentry","category-jsclosuresthis","category-12","tag-javascript"],"_links":{"self":[{"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/posts\/249","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=249"}],"version-history":[{"count":0,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=\/wp\/v2\/posts\/249\/revisions"}],"wp:attachment":[{"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=249"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=249"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.winter-weng.cc\/work\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=249"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}