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Abstract Syntax Tree in Javascript
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Taketoshi Aono(青野健利 a.k.a brn)
January 24, 2018
Programming
0
180
Abstract Syntax Tree in Javascript
JavascriptのASTについて
Taketoshi Aono(青野健利 a.k.a brn)
January 24, 2018
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Transcript
Abstract Syntax Tree in Javascript
Name @brn (ꫬꅿ⨳ⵃ) Occupation ؿٗٝزؒٝسؒٝآص،٥ط؎ذ؍ـؒٝآص، Company Cyberagent ،سذؙأةآؔ AI Messenger
OSS Contributor of V8 Blog http://abcdef.gets.b6n.ch/ Twitter https://twitter.com/brn227 GitHub https://github.com/brn
What is AST? ASTהכJavascriptךفؚٗٓيػ٦أ׃穠卓欰䧭ׁ 圓俑邌植׃加圓鸡ךֿה
if (x) { x = 100 }
IF CONDITION THEN BLOCK EXPRESSION STATEMENT ASSIGN VAR PROXY (X)
LITERAL (100) if (x) { x = 100
Why need it? فؚٗٓيך㶵ךתת⢪ֲךכꨇ׃ְկ javascript㹋遤ׅחכ圫ղזؿؑ٦ؤָ֮կ غ؎ز؝٦س欰䧭ծCFG欰䧭ծIR欰䧭ծ剑黝⻉ծetc…
How do I create it? فؚٗٓىؚٝ鎉铂חכ㛇劤涸חכ俑岀ָ㶷㖈ׅկ JavascriptכEcmaInternationalָ➬圫תהגⰕ׃גְկ
None
Grammars ך⚥ח俑岀ָ㹀纏ׁגְل٦آָ֮ךדֿ撑ֿׅ הדػ٦؟٦剅ֻֿהָדֹկ
None
But… ֿך俑岀㹀纏כ㛇劤涸חךתת⢪ֲךכꨇ׃ְկ
Javascript become too complex Javascriptך俑岀כַז醱꧟חזגֹגֶծ秪磏חךתת ػ٦أֿׅהַָזꨇ׃ְկ
var a = /aaa|bbb/! b / 2 = 0;! !
// Is it easy?! b = / 2 = 0 /! ת׆כ剣せז姻鋉邌植ַ
var a = (x, y) => x + y;! var
a = (x, y);! ! var a = x => x;! var a = x;! ،ٗ٦ꟼ侧
None
var {a: b, b: c} = {b: 1, c: 2};!
({a: b, b: c});! ! [a, b, c] = [0, 1, 2];! [a, b, c];! ⴓⶴ➿Ⰵ
Parser has many state 穠㽷Parserכ㣐ꆀך朐䡾⥂䭯׃זָ갹䓸גػ٦أׅ׃ַז ְկ
AST Usage 蕱⸤׃ג⡲♳־ASTכוֲ⢪גְךַ
In V8 ASTַScope欰䧭׃ׅ ׁח剑穄涸חBytecode欰䧭׃ג㹋遤ׅ YieldװAsync٥Awaitך圓俑JavascriptךStateMachineח㢌䳔ׅ
In Babel AST㢌䳔׃ג剑倜ךJavascriptַ植㖈ךJavascriptפ㢌䳔ׅ
In istanbul AST㢌䳔׃גぐ؝٦سח鸐麓׃⽩➰ֽ؝٦س㙵鴥
Try and play AST Esprima⢪ֲֿהד知⽃חAST欰䧭ֿׅהָדֹ ת https://github.com/estools חػ٦أ׃ASTQuery׃ׅخ٦ָٕ尶㿊֮ךד鑐׃ גה葺ְ
Summary AST鍗ה鸐䌢ךفؚٗٓيדכꨇ׃ַֿהָ葿ղדֹ״ ֲחז 嚂׃ְךד僽ꬊ♧㔐ְֻכ鑐׃גהְְה䙼ֲ