By name: crystal description: Crystal Ruby-like syntax with static typing. Use for .cr files.
Crystal
Crystal compiles to native code (using LLVM) but looks exactly like Ruby. v1.12 continues improving Windows support and parallelism.
When to Use
- Performance sensitive Rubyists: Porting heavy Ruby scripts to Crystal for 50x speedup.
- Microservices: Low memory footprint compared to JVM/Ruby.
- CLI Tools: Fast startup and execution.
Core Concepts
Fibers
Lightweight concurrency (like Go routines). spawn { ... }.
Macros
Generate code at compile time (like Zig/Lisp).
Union Types
String | Int32. The compiler handles the branching.
Best Practices (2025)
Do:
- Use strict types in APIs: Help the compiler with
def foo(x : Int32). - Use
shards: Dependency manager. - Use
-Dpreview_mt: To test multithreading capabilities.
Don't:
- Don't use
eval: Crystal is compiled, there is no runtime eval.