Bend
A massively parallel, high-level programming language
...The tool lets you define variables, functions, or values at the prompt and iteratively refine them—immediately seeing output and types—while preserving state across commands. It emphasizes discoverability and experimentation: users can inspect functions, call them on sample inputs, and evolve logic without a full project scaffold. Because it’s embedded in a graphical or console interface, Bend aims to reduce the friction of switching between editor and runtime when prototyping or debugging ideas in Kotlin. It can also be extended with libraries or domain-specific tools, making it a flexible playground for domain scripting, education, or data exploration.