Modern LLMs are chat models that use Jinja2 templates to format conversations. But Jinja is Python-centric, making deployment hard in C and edge environments. Here's how to build a Jinja2 template engine from scratch in C — covering lexing, parsing, and evaluation — so you can render chat templates natively without Python.
I gave Claude Opus 4.6 and GPT 5.4 the same task: rewrite pigz (a parallel gzip tool) in modern C++23. After 70 minutes, one delivered a clean-room rewrite, the other a wrapper around the old code. Then I pushed the winner to beat pigz — and it did.
Sequence-to-sequence transduction, e.g. neural machine translation (NMT), is a general problem. This task involves transformation of a sequence of symbols to another sequence of symbols, where both input and output can have varying lengths. Challenges Sequential information: Order of input and output symbols are important. Variable length sequences with long term dependencies: Sequences can be extremely long. Symbols may contains dependencies across the sequence. E.g. Consider the text in a book, and dependencies across chapters. Unbounded vocabulary, e.g. Vocabulary in natural languages. Imbalanced distribution: Some symbols may appear frequently while other may appear rarely. E.g. The distribution of types in natural languages. ...
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