DSL for Banking - interactive DSLs

A few weeks ago I posted an M model for a banking transactions. I forgot to post the DSL.

 

Here's a simple DSL that would be quite easy to use. And, it only took me 10 minutes to write it.

module Banking

{

    language BankingLanguage

    {

        interleave Ignorable = ' ' | '\n' | '\t' | '\r';

        

        syntax Main = t:Transaction+

            => Transactions { t };

            

        syntax Transaction =    

            t:TransactionKind 

                a:Amount 

                Transitions 

                Account 

                AccountNumber => { Kind { t }, Amount {a }};

        token Account = "Account";

        token Transitions = "from" | "to";

        token AccountNumber = Digit+;

        token TransactionKind = "Deposit" | "Withdrawal";

        token Amount = CurrencyQualifier? DecimalNumber;

        token CurrencyQualifier = "$";

        token Digit = '0'..'9';

        token DigitWithoutZero = Digit - '0';

        token DecimalNumber = DigitWithoutZero Digit* '.'? Digit+;

    }

}

Here's some sample input:

Withdrawal 200.00 from Account 5

Deposit $3039483.00 to Account 4932

Now, SpankyJ and I were talking (IM'ing actually).

Wouldn't it be cool if you could write a grammar that defining an iteractive textual experience that you could then deploy to a Intellipad session?

Something like this, where you indicate that the syntax is interactive causing the parser to be re-executed with each parse episode termined by the named token, in this case "loop".

         @{Interactive[loop]}

        syntax Main = t:Transaction+

            => Transactions { t };

            

        syntax Transaction =    

            t:TransactionKind 

                a:Amount 

                Transitions 

                Account 

                AccountNumber loop => { Kind { t }, Amount {a }};

        token loop = "\n" | "\r" | "\r\n";

Then, you could have an iterative, transaction-like experience with this particular DSL where people just type in transactions, and get immediate feedback. 

I suppose you'd want the runtime to be hooked up as well... Hmmm - just thinking out loud :)