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POHow to Create an Internal DSL in Scala?
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copied!<p>I have been looking at a couple of books and resources on domain specific languages. I think I want to build an internal DSL in Scala.</p> <pre><code>def instrument = new FXInstrument { provider = "EuroBase" instrumentOrders = List( new FXOrder { baseCcy = "GBP" termCcy = "EUR" legs = List( new FXLeg { amountPrice = 100000.0 spotPrice = 1.56 requirements = List( new FXRequirement { baseCcy="GBP" termCcy="EUR" settlement="Banker Rain" } ) }, new FXLeg { amountPrice = 200000.0 spotPrice = 1.50 requirements = List( new FXRequirement { baseCcy="GBP" termCcy="EUR" settlement="Banker Sunny" } ) } ) } } </code></pre> <p>Such that following asserts are valid:</p> <pre><code> instrument.orders(0).baseCcy should equal ("GBP") instrument.orders(0).termCcy should equal ("EUR") instrument.orders(0).legs(0).amountPrice should equal 100000.0 instrument.orders(0).legs(0).spotPrice should equal 1.56 instrument.orders(0).legs(1).amountPrice should equal 200000.0 instrument.orders(0).legs(1).spotPrice should equal 1.50 instrument.orders(0).legs(0).requirements(0).settlement should equal "Banker Rain" instrument.orders(0).legs(1).requirements(0).settlement should equal "Banker Sunny" </code></pre> <p>I just do not know quite how to implement the domain specific language as an internal representation</p> <p>1) new FXOrder() { /<em>closure</em>/ }</p> <p>I like this syntax, is it good or should I prefer companion objects. For instance I can quickly introduce other FX types easy.</p> <p>2) I want to use "peers" such FXOrder is a scala.Proxy mixee, thus it uses the trait Proxy (mixin)</p> <p>For example ``instrument.peer'' gives the internal peer Java Object of the third party proprietary API (a well known financial services trading system, can you guess?)</p> <p>Ditto for </p> <p>instrument.orders(0).peer instrument.orders(0).legs(0).peer instrument.orders(0).legs(0).requirements(0).peer</p> <p>and so on.</p> <p>I realise that domain specific language is not as simple as I thought, however some pointers on this above, would be really be useful. I would appreciate your responses. Ta!</p> <p><em>PP</em></p>

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