Make small languages for real business work

Start with a rule people need to understand

Imagine a service that cancels an appointment. Its rule says that the person must be offered another date within five working days. Ordinary prose may leave questions: who makes the offer, when the clock starts, what happens when the person cannot attend, and which version of the rule applied?

A small business language can give those distinctions stable names and let a tool check that each rule is complete. DomainLang is developing a method for deciding when that extra structure is useful and how to create it without losing the language of the people who do the work.

A developing method, a proposed common base and working components

The method starts with users, examples and business meaning before choosing syntax. It then covers validation, useful error messages, editing, exchange with other tools and, when needed, execution.

CoreLang has two roles. It is the first worked business-language example, and it is the proposed common syntax and toolchain base that suitable business-related languages can reuse or extend. A language that does not fit that base should be free to take another path.

The toolchain starts from real components. DSLSH connects editors to parsers. THE CREXX Edition demonstrates that connection in a working editor and a limited browser proof of concept. The CREXX tools provide an existing assembly, linking and virtual-machine path for examples that need to run.

Keep the first result small

The first example will cover one rebooking rule. It must show the original business need, the meaning that must be preserved, the proposed language, useful validation messages and the result of trying it in the editor. If execution helps, the example will generate RXAS and use the existing CREXX tools. The work will be successful only if it makes the rule easier to write, review and change.