From 314b49ffa943cf351b1793c3f7d4634c4caee558 Mon Sep 17 00:00:00 2001 From: "google-labs-jules[bot]" <161369871+google-labs-jules[bot]@users.noreply.github.com> Date: Tue, 22 Sep 2026 07:57:43 +0000 Subject: [PATCH 1/2] =?UTF-8?q?=E2=9A=A1=20Bolt:=20Optimize=20Levenshtein?= =?UTF-8?q?=20edit=20distance=20array=20initialization?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Co-authored-by: Tcode-Motion <188012755+Tcode-Motion@users.noreply.github.com> --- .jules/bolt.md | 3 +++ cli/src/main.rs | 31 +++++++++++++++++++++++++------ 2 files changed, 28 insertions(+), 6 deletions(-) diff --git a/.jules/bolt.md b/.jules/bolt.md index 817bbbb5..971eed0e 100644 --- a/.jules/bolt.md +++ b/.jules/bolt.md @@ -32,3 +32,6 @@ ## 2026-09-22 - String allocation optimization in std.web DSL rendering **Learning:** Generating deep HTML structures in `std.web` heavily penalized performance because `dsl_to_html` allocated and returned a new `String` for every child DSL node. This causes `O(N)` heap allocations and redundant copying in the render tree. By passing a mutable `&mut String` buffer recursively downwards, we avoid all intermediate string heap allocations and significantly improve serialization speed. **Action:** Always prefer using a recursive builder pattern passing a single mutable `&mut String` buffer to `write!` or `push_str` when rendering nested tree structures (like HTML, JSON, or ASTs) instead of returning newly allocated strings at each layer. +## 2024-05-24 - Levenshtein Cache Initialization Redundancy +**Learning:** In the Levenshtein distance algorithm, the initialization of the first row (`cache[..] = 0..=len`) can be folded into the first character iteration. By taking advantage of the implicit sequence, you can avoid an explicit array initialization loop entirely, especially since `cache` arrays in inner loops are rapidly mutated and require re-initialization every call. +**Action:** When implementing or optimizing DP matrix algorithms, check if boundary/initialization conditions can be absorbed into the first step of the main loop logic instead of executing as a separate pass. diff --git a/cli/src/main.rs b/cli/src/main.rs index 8110ad3f..80c95f64 100644 --- a/cli/src/main.rs +++ b/cli/src/main.rs @@ -269,16 +269,35 @@ capabilities = ["FileSystem", "Environment", "Process", "Network"] fn levenshtein(a: &str, b: &str, cache: &mut [usize]) -> usize { let b_len = b.len(); - - // We only need bytes since commands are ascii let a_bytes = a.as_bytes(); let b_bytes = b.as_bytes(); - for (i, val) in cache[..=b_len].iter_mut().enumerate() { - *val = i; + if a_bytes.is_empty() { + return b_len; + } + if b_len == 0 { + return a_bytes.len(); + } + + let mut a_iter = a_bytes.iter(); + let &ca = a_iter.next().unwrap(); + let mut temp = 1; + + // Fold the first row initialization into the first loop iteration + // to avoid a redundant loop initialization. + for (j, &cb) in b_bytes.iter().enumerate() { + let next = if ca == cb { + j + } else { + std::cmp::min(j, temp) + 1 + }; + cache[j] = temp; + temp = next; } - for (i, &ca) in a_bytes.iter().enumerate() { - let mut temp = i + 1; + cache[b_len] = temp; + + for (i, &ca) in a_iter.enumerate() { + let mut temp = i + 2; for (j, &cb) in b_bytes.iter().enumerate() { let next = if ca == cb { cache[j] From da9833ec034935eeeb6298bf08cfad6e0d03fe16 Mon Sep 17 00:00:00 2001 From: "google-labs-jules[bot]" <161369871+google-labs-jules[bot]@users.noreply.github.com> Date: Tue, 22 Sep 2026 08:00:15 +0000 Subject: [PATCH 2/2] =?UTF-8?q?=E2=9A=A1=20Bolt:=20Optimize=20Levenshtein?= =?UTF-8?q?=20edit=20distance=20array=20initialization?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Co-authored-by: Tcode-Motion <188012755+Tcode-Motion@users.noreply.github.com>