Speaker: Paul King
Groovy has excellent support for the creation of Domain Specific Languages (DSLs). Such DSLs can be particularly useful when writing business rules. Rules can be written in English-like phrases which are straight-forward to read or write (by non-developers) yet can be fully executable code corresponding to a layer over the top of a traditional logic solving API. This talk illustrates various DSLs, highlights several logic solving APIs and looks at the pros and cons of the various approaches (including tool support, flexibility, lock-in).
Whilst Groovy is the language of choice for this talk, the techniques and principles are not specific to Groovy and apply readily to your favourite modern scripting language. The "logic solving" APIs being highlighted are primarily Choco, Drools Expert and Drools Planner but again these are just illustrative of the logic APIs that you can use when writing a DSL layer. We look at the benefits and costs when writing such DSL layers, numerous real-world examples and the all-important aspects of tooling; covering what non-developer, developer and cloud tooling is available with this kind of approach.
To give a flavour of the talk, here is a snippet from one of the code examples (Einstein’s riddle):
the Briton has a red house the owner of the green house drinks coffee the owner of the yellow house plays baseball the person known to play football keeps birds the man known to play tennis drinks beer the green house is on the left side of the white house the man known to play volleyball lives next to the one who keeps cats the Norwegian lives next to the blue house
When discussing this example, we look at how you create and debug such code, illustrate how several APIs can be used underneath this DSL layer, discuss the costs involved in creating the above DSL in its basic form and in more complex forms that allow type checking, code completion etc. and options for parallelism and cloud deployment.