Session: adding-syntax-highlighting — 2026-03-18

demo-blog-engine · branch feat/syntax-highlight · claude-sonnet-4-6 · 2026-03-18 14:20 · 4 msgs · 12 tools · 1 min read · updated 3 weeks ago

tools: Read, Edit, Bash, Grep
← demo-blog-engine Download .md .txt .json
Tool calls
Edit Edit: 5 calls (41.7%) 5 Read Read: 4 calls (33.3%) 4 Bash Bash: 2 calls (16.7%) 2 Grep Grep: 1 call (8.3%) 1
Token usage40.6K total
Input6.1K
Cache creation9.4K
Cache read22.0K
Output3.1K
Cache hit ratio59%· warming up

Project: demo-blog-engine · Branch: feat/syntax-highlight · Mode: default · Model: claude-sonnet-4-6

Summary

Added syntax highlighting to the blog via syntect. Wired it into the pulldown-cmark code-block callback so fenced code with a language hint gets inline-highlighted HTML. Chose the base16-ocean.dark theme as the default.

Conversation

Turn 1 — User

Add syntax highlighting to code blocks. Use syntect.

Turn 1 — Assistant

Plan: 1. Add syntect = "5" to Cargo.toml 2. Load default syntax + theme sets once at startup 3. In the pulldown-cmark parser, intercept Event::Start(CodeBlock) and replace the body with highlighted_html_for_string

The tricky bit is that pulldown-cmark gives us the code as an Event::Text inside the code-block range, so we need to buffer events between Start(CodeBlock(..)) and End(CodeBlock), then emit a single Html event with the highlighted output.

Tools used in this turn: - Edit: Cargo.toml — added syntect = "5" - Read: src/render.rs (1–80)

Turn 2 — User

Sounds right, go ahead.

Turn 2 — Assistant

Wired it up. Using ClassedHTMLGenerator so we emit class="syntect" and style via an external CSS file rather than inline colours (plays nicer with dark-mode toggle later).

Tools used in this turn: - Edit: src/render.rs — added highlight_block() helper - Bash: cargo build — exit 0 - Bash: cargo run — exit 0

Connections

  • [[demo-blog-engine]] — project
  • [[syntect]] — library
  • [[pulldown-cmark]] — library
  • [[SyntaxHighlighting]] — concept