Summary

In this chapter, you learned the difference between inventing a programming language and inventing a library API to support whatever kinds of computing you want to do. Several different forms of programming language implementations were considered. This first chapter allowed you to think about functional and non-functional requirements for your own language.

These requirements might be different for your language than the example requirements discussed for the Java subset Jzero and the Unicon programming language, which were both introduced.

Requirements are important because they allow you to set goals and define what success will look like. In the case of a programming language implementation, the requirements include what things will look and feel like for the programmers that use your language, as well as what hardware and software platforms it must run on. The look and feel of a programming language include answering both external questions regarding how the language implementation and the programs written in the language are invoked, as well as internal issues such as verbosity: how much the programmer must write to accomplish a given compute task.

You may be keen to get straight to the coding part. Although the classic build-and-fix mentality of novice programmers might work on scripts and short programs, for a piece of software as large as a programming language, we need a bit more planning first. After this chapter’s coverage of the requirements, Chapter 2, Programming Language Design, will prepare you to construct a detailed plan for the implementation, which will occupy our attention for the remainder of this book!