# Sema

> A Scheme-like Lisp with first-class LLM primitives, implemented in Rust.

Sema is a Lisp where prompts are s-expressions, conversations are persistent data structures, and LLM calls are just another form of evaluation. It combines a Scheme core with Clojure-style keywords (`:foo`), map literals (`{:key val}`), and vector literals (`[1 2 3]`).

- 460+ built-in functions across 21 modules
- Multi-provider LLM support (Anthropic, OpenAI, Gemini, Ollama, Groq, xAI, Mistral, and more)
- Tools & agents, structured extraction, conversations, embeddings, vector store
- Cost tracking, response caching, fallback chains, retry with backoff
- Tail-call optimization, macros, modules, error handling
- Available on [crates.io](https://crates.io/crates/sema-lang) as an embeddable Rust crate
- Browser playground at [sema.run](https://sema.run) (WebAssembly)

## Docs

- [Introduction](https://sema-lang.com/docs/index.html): Getting started with Sema
- [CLI Reference](https://sema-lang.com/docs/cli.html): Command-line flags, REPL commands
- [Shell Completions](https://sema-lang.com/docs/shell-completions.html): Tab completion for bash, zsh, fish
- [Editor Support](https://sema-lang.com/docs/editors.html): VS Code, Vim, Emacs, Helix, Zed
- [Embedding in Rust](https://sema-lang.com/docs/embedding.html): Using Sema as a library in Rust projects

## Language Reference

- [Data Types](https://sema-lang.com/docs/language/data-types.html): Numbers, strings, keywords, lists, vectors, maps, etc.
- [Special Forms](https://sema-lang.com/docs/language/special-forms.html): define, lambda, if, cond, let, begin, quote, etc.
- [Macros & Modules](https://sema-lang.com/docs/language/macros-modules.html): defmacro, module system, imports

## LLM Primitives

- [Overview](https://sema-lang.com/docs/llm/index.html): LLM integration overview
- [Completion & Chat](https://sema-lang.com/docs/llm/completion.html): llm/complete, llm/chat, llm/stream
- [Prompts & Messages](https://sema-lang.com/docs/llm/prompts.html): Message construction, prompt templates
- [Conversations](https://sema-lang.com/docs/llm/conversations.html): Multi-turn conversations as immutable data
- [Structured Extraction](https://sema-lang.com/docs/llm/extraction.html): llm/extract, llm/classify, schema-driven output
- [Tools & Agents](https://sema-lang.com/docs/llm/tools-agents.html): deftool, defagent, tool-use loops
- [Embeddings](https://sema-lang.com/docs/llm/embeddings.html): llm/embed, embedding providers
- [Vector Store & Math](https://sema-lang.com/docs/llm/vector-store.html): In-memory vector store, similarity search
- [Caching](https://sema-lang.com/docs/llm/caching.html): Response caching to avoid duplicate API calls
- [Resilience & Retry](https://sema-lang.com/docs/llm/resilience.html): Retry with backoff, rate limiting, fallback chains
- [Providers](https://sema-lang.com/docs/llm/providers.html): Provider configuration, custom providers
- [Cost & Budgets](https://sema-lang.com/docs/llm/cost.html): Budget tracking, dynamic pricing

## Standard Library

- [Overview](https://sema-lang.com/docs/stdlib/index.html): Standard library overview
- [Math & Arithmetic](https://sema-lang.com/docs/stdlib/math.html): Numeric operations, math functions
- [Strings & Characters](https://sema-lang.com/docs/stdlib/strings.html): String manipulation, character operations
- [Lists](https://sema-lang.com/docs/stdlib/lists.html): List operations, higher-order functions
- [Vectors](https://sema-lang.com/docs/stdlib/vectors.html): Mutable vector operations
- [Maps & HashMaps](https://sema-lang.com/docs/stdlib/maps.html): Sorted maps, hash maps, keyword access
- [Predicates](https://sema-lang.com/docs/stdlib/predicates.html): Type checking, equality, comparison
- [File I/O & Paths](https://sema-lang.com/docs/stdlib/file-io.html): File reading/writing, path manipulation
- [PDF Processing](https://sema-lang.com/docs/stdlib/pdf.html): PDF text extraction
- [HTTP & JSON](https://sema-lang.com/docs/stdlib/http-json.html): HTTP client, JSON encode/decode
- [Regex](https://sema-lang.com/docs/stdlib/regex.html): Regular expressions
- [CSV & Encoding](https://sema-lang.com/docs/stdlib/csv-encoding.html): CSV parsing, base64, hex encoding
- [Date & Time](https://sema-lang.com/docs/stdlib/datetime.html): Date/time operations
- [System](https://sema-lang.com/docs/stdlib/system.html): Shell commands, environment, exit
- [Bytevectors](https://sema-lang.com/docs/stdlib/bytevectors.html): Binary data operations
- [Records](https://sema-lang.com/docs/stdlib/records.html): Record types (struct-like)
- [Text Processing](https://sema-lang.com/docs/stdlib/text-processing.html): Text chunking, prompt templates
- [Key-Value Store](https://sema-lang.com/docs/stdlib/kv-store.html): Persistent JSON-backed KV store
- [Context](https://sema-lang.com/docs/stdlib/context.html): Dynamic context/configuration
- [Terminal Styling](https://sema-lang.com/docs/stdlib/terminal.html): ANSI colors, text styling
- [Playground & WASM](https://sema-lang.com/docs/stdlib/playground.html): WASM-specific functions

## Internals

- [Architecture](https://sema-lang.com/docs/internals/architecture.html): Crate structure, dependency flow
- [Bytecode VM](https://sema-lang.com/docs/internals/bytecode-vm.html): Bytecode compiler and virtual machine
- [Bytecode File Format](https://sema-lang.com/docs/internals/bytecode-format.html): .semac binary format specification
- [Evaluator & TCO](https://sema-lang.com/docs/internals/evaluator.html): Trampoline-based tail-call optimization
- [Reader & Spans](https://sema-lang.com/docs/internals/reader.html): Lexer, parser, source spans
- [Performance](https://sema-lang.com/docs/internals/performance.html): Benchmarks, optimization notes
- [Lisp Dialect Benchmark](https://sema-lang.com/docs/internals/lisp-comparison.html): Comparison with other Lisp implementations