Simon Willison compares C vs Rust for SQLite parse_number extension
Original title: parse_number() as a SQLite extension: C vs Rust
The author prompts Claude to explore building a custom SQLite function that parses strings like '-$1,234.56' into numbers, comparing C and Rust implementations on performance and code size.
Simon Willison wondered how easy it would be to write a SQLite C extension adding a parse_number() function. He used Claude to compare building it in C versus Rust, focusing on performance, code complexity, and size of the resulting code. The function would strip commas, dollar signs, pounds, and percent signs, handle a leading minus, and return NULL for unparsable values.
Unconfirmed: No code samples or benchmarks are provided; only the prompting framework and comparison goals.
- Function strips ',', '$', '£', '%' and handles leading '-'
- Returns NULL for unparsable inputs
- Compares C and Rust implementations
- Uses Claude Opus 5.5 for exploration
- Products
- sqlite
- Organizations
- Simon Willison
- AI models
- claude
From the original article
Research: parse_number() as a SQLite extension: C vs Rust I was out walking the dog when I got curious about how easy/difficult it would be to write a SQLite C extension that adds a parse_number() function for turning strings like -$1,234. 56 or '12. 5%' into numeric values that could be summed and sorted.
simonwillison.net
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