--- title: KCL part 2: program memory | daily.dev description: KCL's interpreter faced performance issues from copying entire program memory when defining functions (closures). Two solutions were implemented: first, a... canonical: https://daily.dev/posts/kcl-part-2-program-memory-kwb0zaa5f twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: KCL part 2: program memory | daily.dev og:description: KCL's interpreter faced performance issues from copying entire program memory when defining functions (closures). Two solutions were implemented: first, a... og:url: https://daily.dev/posts/kcl-part-2-program-memory-kwb0zaa5f og:image: https://api.daily.dev/og/posts/kwB0zaa5f.png og:image:alt: KCL part 2: program memory og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # KCL part 2: program memory **[Nick Cameron](https://daily.dev/sources/ncameron)** · 13 min read · 0 upvotes · 0 comments ## Summary KCL's interpreter faced performance issues from copying entire program memory when defining functions (closures). Two solutions were implemented: first, a copy-on-write snapshot mechanism that makes creating snapshots O(1) instead of O(n); second, an epoch counter system inspired by MVCC that tracks value creation time and handles mutation only where needed. Both approaches preserve closure semantics (capturing environment at definition time) while dramatically improving memory efficiency and execution speed. The epoch solution simplified the codebase and enables future optimizations like references in program memory. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [I gave Claude Code, Codex, and Cursor the same memory, and stopped repeating myself](https://daily.dev/posts/i-gave-claude-code-codex-and-cursor-the-same-memory-and-stopped-repeating-myself-aerfqoavv) · XDA Developers · 2 upvotes · 1 comments - [The Weight of Remembering](https://daily.dev/posts/the-weight-of-remembering-eygr4h1b5) · Hacker News · 2 upvotes · 0 comments --- [View this post on daily.dev](https://daily.dev/posts/kcl-part-2-program-memory-kwb0zaa5f) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"KCL part 2: program memory","url":"https://daily.dev/posts/kcl-part-2-program-memory-kwb0zaa5f","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/kcl-part-2-program-memory-kwb0zaa5f"},"datePublished":"2026-02-02T19:04:03.165Z","dateModified":"2026-02-02T19:04:26.561Z","description":"KCL's interpreter faced performance issues from copying entire program memory when defining functions (closures). 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