Everybody Stand Back! I Know Regular Expressions

Transcript

2. @listochkin CTO at Viravix
4. xkcd 2005
10. A language for text manipulations
11. Regular Expressions
14. Used them to describe math of events in neural networks
15. SDS 940 1966 - QED 1968 - Mother of All Demos 1969 - 1st ARPANET IMP node
16. 1966 - Ken Thompson QED 1986 - Henry Spencer regex 1997 - Philip Hazel PCRE
18. /(.*)?\/\/.+[^z]{1,}\1(\b\w+)\s?/
25. Quiz Time!
26. s = s[4] === 's' ? s.substr(8) : s.substr(7); const iQ = s.indexOf('?'); const iH = s.indexOf('#'); const iS = s.indexOf('/'); if (Math.min(iQ, iH, iS) > 0) { return s.substr(0, Math.min(iQ, iH, iS)); } else { return s; }
27. /http[s]?:\/\/(?<domain>[^\?#\/]+)/ .exec(s).groups.domain
28. Math
29. + - * /
30. Trigonometry Complex numbers Integration Derivatives
31. Text
32. substr(3, 5) indexOf(‘a’)
33. Regular Expressions is like a higher-level math for text
34. How do regexes work?
35. SQL CSS selectors File glob patterns
36. DSL
37. Special VM
38. Statically / JIT compiled
39. Often fast even for “slow” languages
40. 2008 JavaScriptCore Regex JIT
41. $("form.add-product button[type=submit]") .on("click", function (e) { ... })
42. /abc/
43. function* enumerate(iterable) { let i = 0; for (const x of iterable) { yield [i, x]; i++; } }
44. function matchAbc(string) { for (const [startPos] of enumerate(string)) { let matchPos = startPos; if (str[matchPos] !== 'a') continue; matchPos += 1; if (str[matchPos] !== 'b') continue; matchPos += 1; if (str[matchPos] !== 'c') continue; return true; } return false; }
46. ababc
47. ababc
48. ababc
49. ababc
50. function matchAbc(string) { for (const [startPos] of enumerate(string)) { let matchPos = startPos; if (str[matchPos] !== 'a') continue; matchPos += 1; if (str[matchPos] !== 'b') continue; matchPos += 1; if (str[matchPos] !== 'c') continue; return true; } return false; }
51. ababc
52. ababc
53. Not smart but predictable
54. Very good for hardware
55. Language
56. Every character is an instruction
57. Most instructions mean “Match this exact character, move forward by one character if matched”
58. /abc|abx/
61. Longer to compile Faster to execute
62. /anteater|antelope|ant/ An ant encountered an anteater
64. /anteater|antelope|ant/ An ant encountered an anteater
66. Put most likely alternative to the left
67. /x*z/
69. /”.*”/
70. I watched “Home Alone” and “Back to the Future” last week
71. I watched “Home Alone” and “Back to the Future” last week
72. I watched “Home Alone” and “Back to the Future” last week
73. I watched “Home Alone” and “Back to the Future” last week
74. I watched “Home Alone” and “Back to the Future” last week
75. I watched “Home Alone” and “Back to the Future” last week
76. I watched “Home Alone” and “Back to the Future” last week
77. I watched “Home Alone” and “Back to the Future” last week
78. I watched “Home Alone” and “Back to the Future” last week
79. /x*z/
80. /x*?z/
83. /”.*”/
84. /”.*?”/
85. I watched “Home Alone” and “Back to the Future” last week
86. I watched “Home Alone” and “Back to the Future” last week
87. I watched “Home Alone” and “Back to the Future” last week
88. I watched “Home Alone” and “Back to the Future” last week
89. I watched “Home Alone” and “Back to the Future” last week
90. I watched “Home Alone” and “Back to the Future” last week
91. I watched “Home Alone” and “Back to the Future” last week
92. How to regex
93. DSL
94. Treat regexes as code
95. Step 1. Formatting
96. function (a){function*b(a){let b=0;for(const c of a)yield[b,c],b++}for(const[c] of b(a)) {let a=c;if("a"===str[a]&&(a+=1,"b"===str[a] &&(a+=1,"c"===str[a])))return!0}return!1}
97. Use extended formatting!
98. /(\d{4})-(\d{2})-(\d{2})/
99. /(?x) # ISO date format \d {4} - \d {2} - \d {2} /
102. function r(re, flags = 'u') { return new RegExp( re .replace(/^(?<regex>.*)(?<!\\)#.*$/gm, '$<regex>') .replace(/\\#/gm, '#') .replace(/\s/gm, ''), flags ); }
103. r(String.raw` # ISO date format \d {4} - \d {2} - \d {2} `)
104. Step 2. Naming
105. /http[s]?:\/\/(?<domain>[^\?#\/]+)/ .exec(s).groups.domain
106. /http[s]?:\/\/([^\?#\/]+)/ .exec(s)[1]
107. function r(re, flags = 'u') { return new RegExp( re .replace(/^(?<regex>.*)(?<!\\)#.*$/gm, '$<regex>') .replace(/\\#/gm, '#') .replace(/\s/gm, ''), flags ); }
108. function r(re, flags = 'u') { return new RegExp( re .replace(/^(.*)(?<!\\)#.*$/gm, '$1') .replace(/\\#/gm, '#') .replace(/\s/gm, ''), flags ); }
109. r(String.raw` # ISO date format (?<year> \d {4}) - (?<month> \d {2}) - (?<day> \d {2}) `)
110. /http[s]?:\/\/(?<domain>[^\?#\/]+)/ .exec(s).groups.domain
111. r(String.raw` http[s]? :// (?<domain> [^?\#/]+ ) # rest of the url `).exec(s).groups.domain
112. Step 3. Structure
113. Perl & PCRE define
114. /(?x) (?&sign)? (?&mantissa) (?&exponent)? (?(DEFINE) (?<sign> [+-] ) (?<mantissa> \d++\.?+\d*+ | \. \d++ ) (?<exponent> [eE] (?&sign)?+ \d++ ) ) /
115. Yes, even recursion
116. /(?x) (?(DEFINE) (?<object> \{ (?&nvp) [, (?&nvp)]* \}) (?<nvp> (?&name) : (?&value) ) (?<value> (?&number) | (?&boolean) | (?&string) | (?&object) | (?&array) ) ... ) (?&value) /
117. JSON parsing Regex
118. use PPR; my $perl_block = qr{ (?&PerlBlock) $PPR::GRAMMAR }x;
119. 1860 lines
120. Отвал башки
123. Raku grammars
124. / :my regex sign { <[+-]> } :my regex mantissa { \d+: '.'?: \d*: | '.' \d+: } :my regex exponent { <[eE]> <sign>?: \d+: } <sign>? <mantissa> <exponent>? /
125. function r(re, flags = 'u') { return new RegExp( re .replace(/^(?<regex>.*)(?<!\\)#.*$/gm, '$<regex>') .replace(/\\#/gm, '#') .replace(/\s/gm, ''), flags ); }
126. [2020-09-11T15:57:20.848Z - 099fe80d-7e11-4c47-9bbf-2372bd6b2527: 108ms] 200 OK GET /configuration-tree/8 <- http://web.app.ui/ 178.133.180.67 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:82.0) Gecko/20100101 Firefox/82.0' {"id":1,"email":"andrei.listochkin@viravix.com",...}
127. [Time in UTC - Request ID: Response Time] [2020-09-11T15:57:20.848Z - 099fe80d-7e11-4c47-9bbf-2372bd6b2527: 108ms] Status Code and Message Request Method and Path <- Refer URL User IP 200 OK GET /configuration-tree/8 <- http://web.app.ui/ 178.133.180.67 User Agent 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:82.0) Gecko/20100101 Firefox/82.0' Session Token {"id":1,"email":"andrei.listochkin@viravix.com",...}
128. ^ \[ (?<requestDate>2020-0[789]\S+) \s - \s (\S+) # request ID : \s (?<requestDuration>\d+)ms ] \s .+ \s (?<session>\S+) (?<!null) # non-anonymous sessions only $
129. const match = lineRe.exec(logLine); if (match) { const { requestDate, requestDuration, session } = match; const requestData = { date: new Date(requestDate), duration: parseInt(requestDuration, 10), email: JSON.parse(session).email } }
130. Regexes are awesome.
131. Üñiçødé aware
132. Advanced “math” on text
133. Declarative
134. Maintainable
136. Your best friend when it comes to text processing