CakeML/cakeml
Apr 2025 – Feb 2026
6 Months active
Languages Used
MLSMLStandard MLMarkdown
Technical Skills
Abstract Syntax TreesBuild System ManagementCode CleanupCode RefactoringCompiler DesignCompiler Development
Johannes Åman Pohjola
PROFILE
Johannes Åman Pohjola
Over six months, contributed to the CakeML/cakeml repository by developing and verifying core compiler features, focusing on global variable handling, parser enhancements, and formal proof integration. Leveraged SML and Standard ML to implement language parsing, intermediate representation transformations, and static analysis, while systematically reducing global state and improving modularity. Advanced the compiler’s correctness through theorem proving and formal verification, ensuring safe code generation and robust semantics preservation. Addressed critical bugs in code generation and proof scripts, refined function record support, and maintained build health. The work emphasized maintainability, cross-platform portability, and end-to-end traceability across the compiler and verification pipeline.
Overall Statistics
Feature vs Bugs
46%Features
Repository Contributions
171Total
Bugs
68
Commits
171
Features
59
Lines of code
1,616,923
Activity Months6
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37 peopleShared Repositories
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Jared YeagerMember
Work History
February 2026
2 Commits
Feb 1, 2026February 2026 monthly summary for CakeML/cakeml focusing on stability and correctness improvements in the Pancake compiler.
2 Commits
Feb 1, 2026February 2026 monthly summary for CakeML/cakeml focusing on stability and correctness improvements in the Pancake compiler.
February 2026
August 2025
41 Commits • 22 Features
Aug 1, 2025August 2025: Delivered end-to-end support for function records in CakeML/cakeml, strengthened formal verification, and enhanced global-variable handling, driving improved correctness, expressiveness, and release readiness. Key features delivered: - Added @top keyword for concise syntax and selector semantics. - Present function declarations as records to unify IR representations. - Updated ptree conversion, pancake semantics, and panProps for function records to ensure consistent tooling and proofs. - Strengthened formal proofs around function records, including pan_globalsProof and pan_to_wordProof along with Call-case enhancements. - Globals support in AssignCall with examples showing globals return. Release and quality: updated NEWS.md and release notes; code cleanup and merge fixes. Business impact: improved reliability, enabling new coding patterns, and faster onboarding for contributors.
August 2025
41 Commits • 22 Features
Aug 1, 2025August 2025: Delivered end-to-end support for function records in CakeML/cakeml, strengthened formal verification, and enhanced global-variable handling, driving improved correctness, expressiveness, and release readiness. Key features delivered: - Added @top keyword for concise syntax and selector semantics. - Present function declarations as records to unify IR representations. - Updated ptree conversion, pancake semantics, and panProps for function records to ensure consistent tooling and proofs. - Strengthened formal proofs around function records, including pan_globalsProof and pan_to_wordProof along with Call-case enhancements. - Globals support in AssignCall with examples showing globals return. Release and quality: updated NEWS.md and release notes; code cleanup and merge fixes. Business impact: improved reliability, enabling new coding patterns, and faster onboarding for contributors.
July 2025
10 Commits
Jul 1, 2025July 2025 monthly review for CakeML/cakeml emphasizing bug fixes and code cleanup to stabilize verification, with no new user-facing features delivered this period. Focused efforts improved proof integrity, reduced code complexity, and streamlined the verification pipeline, delivering measurable technical and maintainability value.
10 Commits
Jul 1, 2025July 2025 monthly review for CakeML/cakeml emphasizing bug fixes and code cleanup to stabilize verification, with no new user-facing features delivered this period. Focused efforts improved proof integrity, reduced code complexity, and streamlined the verification pipeline, delivering measurable technical and maintainability value.
July 2025
June 2025
21 Commits • 6 Features
Jun 1, 2025Month: 2025-06 | CakeML/cakeml Overview: Focused on strengthening formal verification, ensuring safe global code generation, and enabling localization readiness. Delivered core correctness proofs for global and word-level semantics, plus a set of focused bug fixes to close critical gaps in localised_exp, pan_to_word, and pan_to_target proofs. The work reduces release risk, improves portability across 64/32-bit targets, and lays groundwork for localization across platforms. Key accomplishments (selected top achievements): - Proved that pan_globals produces globals-free code (commit 3cf7e99379503c9c9e10a167f2cf14ebdf0c73f4). - Proved pan_to_word semantics preservation (commit a8cb2a15b5f329183f867ed564b78228fbfb7927). - Generalised pan_to_wordProof (commit 23d6470229deec67f6c66947ff0c7e8bc39a903c). - Translated pan_globals and friends to support localization (commit 199cc519a05f429bd63cfaec0519d426fdb978ee). - Specialised exception word width in get_eids (commit 1e23e1de64d0b3c2c12f8255d64eb0b2b6bab652). Top bugs fixed (selected significant fixes): - Localised expression completeness: Add missing clauses to localised_exp (commit 1823af47b4dea4180293197d6a23fef074b66d00). - Every_exp clause completeness (commit d7b26f72bbdd6622210a194a71c155e3301cba6c). - pan_to_wordProof correctness fix (commit 15f19da45796b7316231a16fb6da13b069d1348b). - Pan_to_target fix (commit 1ec722aeb4dda81110378b9febc6b38ca05c1578). - Remove stray assumption in proofs (commit e24770172e566fea5610df2e6c8fbec1ce01e66b). - Weaken crep_to_loopProof assumption (commit ab73b8c27c279be70c8ae8296ef66cd3a45aaa0a). - Fix overpolymorphism of get_eids in pan_to_wordProof (commit 7fff520240e9c14c19554341d3f4f39d557d1368). - Change compilation of top_addr in loop_to_word (commit d8ea079fa9478b6261427c91df7d8dbf1a66baa7). - Fix pan_to_wordProof for new top_addr compilation (commit 8e272ac0c9262fd155f38ad5b7083bb4c7e883ae). - Propagate pancake parser name change (commit bd8f500ffee595a0aba92ff8d754adbbcb7f3e6d). - Prove remaining cheats in pan_to_targetProof (commit 1ca7d9112221dd68d9affe65f23b8af19e029910). - Add a forgotten base case (commit 18a8327ce3cdddd50c36736df8c7e46fa2cb5b73). - Apply 64-bit globals translation changes to 32-bit (commit 8c8efe486abf792876fd0e19d5baea5f255ffe01). Technology stack and skills demonstrated: formal verification, Coq/interactive theorem proving and code translation tooling, cross-bit portability (64-/32-bit), and localization tooling integration.
June 2025
21 Commits • 6 Features
Jun 1, 2025Month: 2025-06 | CakeML/cakeml Overview: Focused on strengthening formal verification, ensuring safe global code generation, and enabling localization readiness. Delivered core correctness proofs for global and word-level semantics, plus a set of focused bug fixes to close critical gaps in localised_exp, pan_to_word, and pan_to_target proofs. The work reduces release risk, improves portability across 64/32-bit targets, and lays groundwork for localization across platforms. Key accomplishments (selected top achievements): - Proved that pan_globals produces globals-free code (commit 3cf7e99379503c9c9e10a167f2cf14ebdf0c73f4). - Proved pan_to_word semantics preservation (commit a8cb2a15b5f329183f867ed564b78228fbfb7927). - Generalised pan_to_wordProof (commit 23d6470229deec67f6c66947ff0c7e8bc39a903c). - Translated pan_globals and friends to support localization (commit 199cc519a05f429bd63cfaec0519d426fdb978ee). - Specialised exception word width in get_eids (commit 1e23e1de64d0b3c2c12f8255d64eb0b2b6bab652). Top bugs fixed (selected significant fixes): - Localised expression completeness: Add missing clauses to localised_exp (commit 1823af47b4dea4180293197d6a23fef074b66d00). - Every_exp clause completeness (commit d7b26f72bbdd6622210a194a71c155e3301cba6c). - pan_to_wordProof correctness fix (commit 15f19da45796b7316231a16fb6da13b069d1348b). - Pan_to_target fix (commit 1ec722aeb4dda81110378b9febc6b38ca05c1578). - Remove stray assumption in proofs (commit e24770172e566fea5610df2e6c8fbec1ce01e66b). - Weaken crep_to_loopProof assumption (commit ab73b8c27c279be70c8ae8296ef66cd3a45aaa0a). - Fix overpolymorphism of get_eids in pan_to_wordProof (commit 7fff520240e9c14c19554341d3f4f39d557d1368). - Change compilation of top_addr in loop_to_word (commit d8ea079fa9478b6261427c91df7d8dbf1a66baa7). - Fix pan_to_wordProof for new top_addr compilation (commit 8e272ac0c9262fd155f38ad5b7083bb4c7e883ae). - Propagate pancake parser name change (commit bd8f500ffee595a0aba92ff8d754adbbcb7f3e6d). - Prove remaining cheats in pan_to_targetProof (commit 1ca7d9112221dd68d9affe65f23b8af19e029910). - Add a forgotten base case (commit 18a8327ce3cdddd50c36736df8c7e46fa2cb5b73). - Apply 64-bit globals translation changes to 32-bit (commit 8c8efe486abf792876fd0e19d5baea5f255ffe01). Technology stack and skills demonstrated: formal verification, Coq/interactive theorem proving and code translation tooling, cross-bit portability (64-/32-bit), and localization tooling integration.
May 2025
53 Commits • 20 Features
May 1, 2025Month: 2025-05 | Repository: CakeML/cakeml Overview: Focused on correctness, reliability, and maintainability across the compiler, proof system, and static checker. Delivered concrete feature progress, high-impact bug fixes, and foundational work enabling secure, verifiable code generation and easier future maintenance. Key features delivered: - Bug fix: Fix Call case in compiler (adbb41069bd69b4e87452cc494b9be2b325d4907) — corrected Call-path handling in the compiler backend, reducing miscompilation risk. - Proof system progress: Implemented significant progress on compiler proofs with multiple simplifications and finalization of pan_simpProof (1fd8baa39aa848b0ec5eeaecce2037b4804db52f; 010fea9c0c99e9353101590daa1b5b6fe5a67a38; 749824ef39685b3c336502778c242ca61e591d2f; 20f0006e18165d5bebb1b5f0eda3f9f0fbb04df8; a6f093191d2d1ef04662cbbdb4ba0ab7b51f8ffc; 82f4655778fa8364612af97a13974b0738be6ce6). - Pan_globalsProof refinements and cheat-detection: Flesh out pan_globals sketch, progress the pan_globals proof, and refine cheats to strengthen correctness and cheat-resilience; culminating in pan_globalsProof refinements/finalization (b8b0a642b3ff78459faf80533a796819791aaffe; 60795a03a08926f71f3c22b1db64f2302deeeb46; dfb440d576263c5014d8ad7003a0076ddf0407b9; 3deefe585d889eb50ec270fbf388d9fb9cad56b4; 7f35724fe570faff8933f6fd0427cb501c418547; bdfc5b5a6c3597089175843bf3bef4a319e41e82; 08b9e9241fd06bb703ce102a1eb9391caab09d55). - Globals initialisation and compilation enhancements: Partially defined and proven globals initialization; added more detail to globals compilation to align proofs with compilation steps (106c597b0b4f785805745bd466f0185e30375026; fa7da7d41a8989f1534a8ddf8a5305aedbcfced2). - Fresh name generation and pancake proofs: Implemented fresh name generation and expanded pancake property proofs (f41907081bd3e872b55d462e35fd64591bdab6c6; 5fe43ed84421e2282c578cfb66f1b29753525705). Major bugs fixed: - Fix Call case in compiler (adbb41069bd69b4e87452cc494b9be2b325d4907) - Fix pan_to_crepProof (eb49b1f463a15b3c0a9d994a206859392bc2478b) - Fix type error (28670fc05f77030acd1011647acf79d828d827b7) - Verify resort_decls (7f5bdc4d8fad57a7769f3599487ef7d6d5f7746d) - Nonsensical clause order fix (1a45e71afd348988690643d20f3d3df3008a365e) - Fix miscalculated offset (e4e497e271a1d628cd62a3f2bb0a249535c5461e) - Remove duplicate lemma (e62be0d80cc18fdf43c0c0cab294ef259c23bf50) - Remove superfluous assumption (eca035134ac79389c6a8aa7937b9d30c2d2b4655) - Remove vacuous quantifier (ed180ec36a0fb00a4ed7b61811afa6e561c54878; 0080ef8ffe43c6eb1d413150406e87975ce87fb7) - Parser fix for removal of labels (0dbdc0c5f420b454fe74365c2f71f052848bb307) Overall impact and accomplishments: - Increased reliability and correctness across the compiler, proof system, and static checker, reducing regression risk and providing a stronger foundation for secure, verifiable code generation and future feature work. The work completed this month improves maintainability, reduces debugging time for future changes, and enables broader confidence in automated proofs and optimizations. Technologies/skills demonstrated: - Formal verification and proof engineering (lemma development, proof simplifications, and automation). - Compiler backend correctness and resilience to edge cases (Call-path fixes, proof-backed ensuring correctness). - Static analysis and tooling improvements (static checker enhancements, shadow-warning integrations, and global variable safety checks). - End-to-end traceability via structured commits supporting reproducibility and audits.
53 Commits • 20 Features
May 1, 2025Month: 2025-05 | Repository: CakeML/cakeml Overview: Focused on correctness, reliability, and maintainability across the compiler, proof system, and static checker. Delivered concrete feature progress, high-impact bug fixes, and foundational work enabling secure, verifiable code generation and easier future maintenance. Key features delivered: - Bug fix: Fix Call case in compiler (adbb41069bd69b4e87452cc494b9be2b325d4907) — corrected Call-path handling in the compiler backend, reducing miscompilation risk. - Proof system progress: Implemented significant progress on compiler proofs with multiple simplifications and finalization of pan_simpProof (1fd8baa39aa848b0ec5eeaecce2037b4804db52f; 010fea9c0c99e9353101590daa1b5b6fe5a67a38; 749824ef39685b3c336502778c242ca61e591d2f; 20f0006e18165d5bebb1b5f0eda3f9f0fbb04df8; a6f093191d2d1ef04662cbbdb4ba0ab7b51f8ffc; 82f4655778fa8364612af97a13974b0738be6ce6). - Pan_globalsProof refinements and cheat-detection: Flesh out pan_globals sketch, progress the pan_globals proof, and refine cheats to strengthen correctness and cheat-resilience; culminating in pan_globalsProof refinements/finalization (b8b0a642b3ff78459faf80533a796819791aaffe; 60795a03a08926f71f3c22b1db64f2302deeeb46; dfb440d576263c5014d8ad7003a0076ddf0407b9; 3deefe585d889eb50ec270fbf388d9fb9cad56b4; 7f35724fe570faff8933f6fd0427cb501c418547; bdfc5b5a6c3597089175843bf3bef4a319e41e82; 08b9e9241fd06bb703ce102a1eb9391caab09d55). - Globals initialisation and compilation enhancements: Partially defined and proven globals initialization; added more detail to globals compilation to align proofs with compilation steps (106c597b0b4f785805745bd466f0185e30375026; fa7da7d41a8989f1534a8ddf8a5305aedbcfced2). - Fresh name generation and pancake proofs: Implemented fresh name generation and expanded pancake property proofs (f41907081bd3e872b55d462e35fd64591bdab6c6; 5fe43ed84421e2282c578cfb66f1b29753525705). Major bugs fixed: - Fix Call case in compiler (adbb41069bd69b4e87452cc494b9be2b325d4907) - Fix pan_to_crepProof (eb49b1f463a15b3c0a9d994a206859392bc2478b) - Fix type error (28670fc05f77030acd1011647acf79d828d827b7) - Verify resort_decls (7f5bdc4d8fad57a7769f3599487ef7d6d5f7746d) - Nonsensical clause order fix (1a45e71afd348988690643d20f3d3df3008a365e) - Fix miscalculated offset (e4e497e271a1d628cd62a3f2bb0a249535c5461e) - Remove duplicate lemma (e62be0d80cc18fdf43c0c0cab294ef259c23bf50) - Remove superfluous assumption (eca035134ac79389c6a8aa7937b9d30c2d2b4655) - Remove vacuous quantifier (ed180ec36a0fb00a4ed7b61811afa6e561c54878; 0080ef8ffe43c6eb1d413150406e87975ce87fb7) - Parser fix for removal of labels (0dbdc0c5f420b454fe74365c2f71f052848bb307) Overall impact and accomplishments: - Increased reliability and correctness across the compiler, proof system, and static checker, reducing regression risk and providing a stronger foundation for secure, verifiable code generation and future feature work. The work completed this month improves maintainability, reduces debugging time for future changes, and enables broader confidence in automated proofs and optimizations. Technologies/skills demonstrated: - Formal verification and proof engineering (lemma development, proof simplifications, and automation). - Compiler backend correctness and resilience to edge cases (Call-path fixes, proof-backed ensuring correctness). - Static analysis and tooling improvements (static checker enhancements, shadow-warning integrations, and global variable safety checks). - End-to-end traceability via structured commits supporting reproducibility and audits.
May 2025
April 2025
44 Commits • 11 Features
Apr 1, 2025April 2025 focused on stabilizing CakeML/cakeml frontend and reducing global state while expanding parser capabilities and language features. Key features delivered include global variables handling improvements with draft semantics and improved presentation, plus shape annotations to enhance verification and tooling. A TopAddr primitive was added to enable more efficient address handling. Parser enhancements were completed to understand top-level declarations and manage local variables properly, improving reliability in code that compiles from user sources. A global cleanup pass was sketched to remove globals, supporting better modularity and easier future refactors. TimeLang upkeep was performed by removing stray files and debris, improving maintainability and build health. In addition, localised_prog, pan_simp, and pancake-related declarations progressed, while a broad set of bug fixes (ptree conversion, panProps, pan_simp, loop_to_wordProof, crep_to_loopProof, duplicate definitions, and label removal) reduced regressions and improved stability.
April 2025
44 Commits • 11 Features
Apr 1, 2025April 2025 focused on stabilizing CakeML/cakeml frontend and reducing global state while expanding parser capabilities and language features. Key features delivered include global variables handling improvements with draft semantics and improved presentation, plus shape annotations to enhance verification and tooling. A TopAddr primitive was added to enable more efficient address handling. Parser enhancements were completed to understand top-level declarations and manage local variables properly, improving reliability in code that compiles from user sources. A global cleanup pass was sketched to remove globals, supporting better modularity and easier future refactors. TimeLang upkeep was performed by removing stray files and debris, improving maintainability and build health. In addition, localised_prog, pan_simp, and pancake-related declarations progressed, while a broad set of bug fixes (ptree conversion, panProps, pan_simp, loop_to_wordProof, crep_to_loopProof, duplicate definitions, and label removal) reduced regressions and improved stability.
Activity
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Quality Metrics
Correctness90.2%
Maintainability86.0%
Architecture85.6%
Performance76.6%
AI Usage20.2%
Skills & Technologies
Programming Languages
MLMarkdownSMLStandard ML
Technical Skills
Abstract Syntax Tree (AST)Abstract Syntax TreesAssembly GenerationBuild System ManagementCode CleanupCode FormattingCode RefactoringCompiler DesignCompiler DevelopmentCompiler TheoryDocumentationExample GenerationFormal MethodsFormal SemanticsFormal Verification
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