Implementing a Forth

Implementing a Forth language involves several key considerations and steps, as demonstrated by various experiences and insights from experienced Forth programmers. Here's a detailed look at the process: 1. **Starting Point**: Forth implementation often begins with a decision to either port an existing Forth system or start from scratch. Porting an existing Forth, such as JONESFORTH by Richard WM Jones, can serve as a practical starting point. This involves adapting the core Forth written in a host language or machine code to your target platform. 2. **Understanding the Language**: Forth is known for its concatenative programming style, which can significantly influence how one thinks about programming and computer architecture. Implementing Forth can thus be a journey into the heart of programming fundamentals. 3. **Technical Challenges**: Implementing a Forth interpreter, as experienced by Lawrence in his project, reveals that while Forth's stack-based nature might initially seem limiting, it is actually Turing-complete and capable of accessing memory and performing complex operations. Writing an interpreter in assembly for an old CPU like the Z80 on a machine like the TRS-80 serves as a testament to Forth's versatility and the feasibility of implementing it in various environments. 4. **Performance Considerations**: Forth can be used for high-performance applications, especially in numerical computing, due to its direct memory access capabilities and the efficiency of its stack-based operations. This makes it a viable choice for performance-critical systems. 5. **Learning and Resources**: Implementing Forth can be a learning experience in itself, offering insights into language design and implementation. Resources such as tutorials and existing Forth systems can serve as guides, especially for those new to the language. In conclusion, implementing a Forth language requires a deep dive into the principles of concatenative programming and a willingness to explore the technical nuances of the language. Whether starting from a port of an existing Forth or beginning anew, understanding Forth's core principles and its capabilities in terms of performance and versatility is crucial. The process can be both educational and rewarding, offering a unique perspective on programming and computer architecture.