Parsing for Fun and Profit

Parsingfor Fun and Profit(but mainly fun)

Ash Moranash.moran@patchspace.co.uk

PatchSpace LtdSaturday, 23 February 13

Saturday, 23 February 13

Parsing

Adding structure and meaning to text

Parsing Human Languages

Jake stretched his legs“Jake”, “stretched”, “his”, “legs”“Jake”<noun>, “stretched”<verb, past>, “his”<possessive pronoun>, “legs”<noun>“Jake” <noun, subject>, “stretched”, (“his”, “legs”)<noun phrase, object>

Parsing Computer Languages

“foo = bar + 123”“foo”, “=”, “bar”, “+”, “123”“foo”<var>, “=”<assignment_op>, “bar”<var>, “+”<op_plus>, “123”<int_literal>

Not just compiling!Compilers breathe fire.

Pretty PrintingSaturday, 23 February 13

Pretty Printing

http://gofmt.com/

Code Smell Detectorshttps://rubygems.org/gems/reek

Code Smell DetectorsSaturday, 23 February 13

Other ideasCode metricsBug detectorsDomain-specific languagesLanguage translators (e.g. Ruby -> PHP)Code obfuscatorsAlternative syntaxes (e.g. CoffeeScript)Refactoring tools

Step 13 year computer science

degree

Lexing/Tokenising

if x > 100 then return “big” else return “small”if x > 100 then return “big” else return “small”

Tree Buildingif x > 100 then return “big” else return a + b

return

“big”

return

Parsing Expression Grammars

Like regular expressions, but can handle recursion, e.g. HTMLNot actually that much harder to use

Regexes and HTML

Treetop PEG grammarSaturday, 23 February 13

Doing Sums

Switch to Sublime Text, idiot

Code is now available:https://github.com/patchspace/parsing_for_fun_and_profit/

A Ruby Syntax Highlighter

A tool to read in simple Ruby source and output syntax highlighted HTML

Because I thought it would be funIt wasBecause I thought it would be easy…

HowBuild a parse tree of the Ruby sourceWalk the tree and spit out a <span> element for each bit of textOh yes, make sure each line goes in <div> and <pre> tagsWrap it in <html>And for bonus points, do some fancy method highlighting

Switch to Chrome, idiot

Switch to Sublime Text again, idiot

Code is now available:https://github.com/patchspace/parsing_for_fun_and_profit/

We’re doing this the hard way

Ruby’s grammar is too complex and undefined to easily implement as a PEGTools for parsing Ruby already exist

Ripper (Ruby 1.9.3)Saturday, 23 February 13

Learn more!

Skip theoretical physics, start by playing with Lego

Do moreIdeas you might like to try:

CSV parserJSON parser (return arrays & hashes)XML parserJSON highlighterA simple JavaScript minifier (just kill whitespace)

Thank you

Ash Moranash.moran@patchspace.co.uk

PatchSpace LtdSaturday, 23 February 13

Parsing for Fun and Profit

Technology

Microapps for Fun and profit

Productization For Fun & Profit

Stack switching for fun and profit

Abusing RFID for fun & profit. - conference.hackinthebox.orgconference.hackinthebox.org/hitbsecconf2011kul/materials/D1 SIGINT... · Abusing RFID for fun & profit. Youri ”iTdeal”

Finger Pointing for Fun, Profit and War?Profit and War? · Finger Pointing for Fun, Profit and War?Profit and War? Tom Parker tom.at.rooted.dot.net

Crowdfunding for Fun and Profit

for Fun and Profit - pages.cs.wisc.edu

Pinterest for fun and profit

Docker for Fun and Profit

Programming Android for fun and profit · Tristan Roddis, Cogapp. Barcamp Brighton Programming Android for fun and profit

Publishing eBooks for Traffic, Profit & Fun

Hacking for Fun and Profit

Fun & profit with bug bounties

Calendars for fun and profit

Autoscaling for fun and profit

Seaching Shodan For Fun And Profit

XSS for Fun and Profit

Fun and games for profit

R/ quantstrat For Fun & Profit

ES6: For Fun & Profit