Jirka Maršík
Member Of Technical Staff at Oracle Labs
Prague, Prague, Czechia
Summary
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Rockstar🎓
Top SchoolJirka Maršík is a Member of Technical Staff at Oracle Labs with 15 years of experience building high-performance language runtimes and developer tooling. He contributes deep backend expertise to GraalVM projects (GraalPython, GraalJS, TruffleRuby), focusing on regex engines, language compatibility and test-suite integration for ECMAScript and Ruby. His background in computational linguistics and a PhD informs pragmatic handling of string/regex edge cases and robust test coverage across multiple VMs. He has a track record of improving language interoperability and instrumentation, including adapting TRegex and test262/testV8 suites for GraalVM. Based in Prague, he combines academic rigor from multiple international degrees with hands-on production work at Oracle Labs. An often-overlooked strength is his ability to bridge formal language semantics with engineering pragmatism to stabilize complex runtime behavior.
15 years of coding experience
Master 1, Computer Application Technology, GPA 3.67, Master 1, Computer Application Technology, GPA 3.67 at Shanghai Jiao Tong UniversityGymnázium J. K. TylaPhD, Computer Science, PhD, Computer Science at Universite de LorraineBachelor 3, Computer Science, GPA 3.84, Bachelor 3, Computer Science, GPA 3.84 at Univerzita Karlova v PrazeMaster, Computer Science, Master, Computer Science at Erasmus Mundus Language and Communication Technologies Programme
Czech, English, French
Stackoverflow
1reputation
0reached
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Github Skills (17)
spec10
javascript10
python10
graalvm10
testing10
java10
ruby10
regular-expression10
javas10
rubyspec10
html10
truffle10
test-suite10
ecmascript10
test-automation10
Programming languages (12)
Github contributions (5)
oracle/graaljs
Jan 2018 - Aug 2022
GraalJS – A high-performance, ECMAScript compliant, and embeddable JavaScript runtime for Java
Role in this project:
Backend Developer
Backend DeveloperContributions:302 commits, 9 comments, 4 issues in 4 years 8 months
Contributions summary:Jirka primarily contributed to the GraalJS project, a high-performance JavaScript runtime. Their work involved modifying Java files related to instrumentation tests, including `CallAccessTest.java`. They also updated test262 and testV8, which are test suites used for JavaScript engine validation. Additionally, the user made changes to source code files in the `src/com.oracle.js.parser` directory.
polyglotnode-jscompliantjavascriptinteroperability
compat-table/compat-table
Jan 2019 - Aug 2022
ECMAScript compatibility tables
Role in this project:Full-stack Developer
Full-stack DeveloperContributions:1 review, 23 commits, 2 PRs in 3 years 8 months
Contributions summary:Jirka primarily contributed to the ECMAScript compatibility tables project, focusing on testing and updating results for various JavaScript engines, including GraalVM. Their work involved modifying test runner scripts and updating test results across multiple HTML files, including those for ES2016plus, ES6, and ESNext features, to reflect the behavior of different JavaScript versions. They also made changes to the test runner itself to better accommodate GraalVM's specific features. The user has also implemented the --js.intl-402 flag.
jsjavascriptcompatibilityecmascript
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