14.9. Tips for Developing DSLs

Write representative samples of the rules your application requires and test them as you develop.

Rules, both in DRL and in DSLR, refer to entities according to the data model representing the application data that should be subject to the reasoning process defined in rules.

Writing rules is easier if most of the data model's types are facts.

Mark variable parts as parameters. This provides reliable leads for useful DSL entries.

You may postpone implementation decisions concerning conditions and actions during this first design phase by leaving certain conditional elements and actions in their DRL form by prefixing a line with a greater sign (">"). (This is also handy for inserting debugging statements.)

New rules can be written by reusing the existing DSL definitions, or by adding a parameter to an existing condition or consequence entry.

Keep the number of DSL entries small. Using parameters lets you apply the same DSL sentence for similar rule patterns or constraints.