dsl

Apologies if this question has been answered before. I want to insert a small DSL into a server application I work on. The syntax is very simple and even at this early stage I am stumped. I just can't get my head around how to construct the syntax in spirit. Here is an example of the syntax I want to test for: WHERE [not] <condition> [ and | or <condition> ] <command> [parameters] The WHERE clause will select a number of objects from an internal store by testing named properties on them. The vector of selected objects is then passed as input to the command object. There are 2 possible tests I

I've got a bit of fettish for language design and I'm currently playing around with my own hobby language. ( http://rogeralsing.com/2010/04/14/playing-with-plastic/ ) One thing that really makes my mind bleed is "generators" and the "yield" keyword. I know C# uses AST transformation to transform enumerator methods into statemachines. But how does it work in other languages? Is there any way to get generator support in a language w/o AST transformation? e.g. Does languages like Python or Ruby resort to AST transformations to solve this to? (The question is how generators are implemented under

we have developped application based on Karaf and Apache Camel. While our application is entirely based on bundles ( OSGI ) we are also loading the Camel context ( and its' Route Contexts ) on startup, whcih would mean that we have defined some static routes. My question is. Is there a way to dynamically LOAD routes while the application is running without the need to reread the Camel Context as this will reset/restart the already existing routes. The same would apply to already created routes, for example if we want to edit a route whcih already exist. The whole idea is that we are planning

I just came across very nice tool Xtext to create DSL as well as IDE for editing. I did some search on the web and found people saying it does not provide all the features of ANTLR. I am using ANTLR as my parser generator. I am not even sure what features of ANTLR I will need to write complete parser for my language but ANTLR is around for quite a long time and probably supports more features than Xtext. Can anyone please give some examples of what CANNOT be specified in a Xtext grammar? You cannot specify semantic predicates in an Xtext grammar. Furthermore it's not possible to include

Is there a way to restrict extension methods in DSLs? Say I have a class structure like this: class Outer { fun middle(op: Middle.() -> Unit): Middle { val middle = Middle() middle.op() return middle } } class Middle { fun inner(op: Inner.() -> Unit): Inner { val inner = Inner() inner.op() return inner } } class Inner fun outer(op: Outer.() -> Unit): Outer { val outer = Outer() outer.op() return outer } I can then create a call like so: outer { middle { inner { middle { } // Here is the problem } } } My problem is that the marked middle { } call is confusing, as it adds a Middle to the Outer

An instance of a class, in Java, can access private fields of a different instance of its own type, such as in the following listing: public class Foo { private int secret; public void bar(final Foo foo) { foo.secret = 100; } } What would be the argument for such semantics (when designing a language)? Well, first you have to ask "why have private fields at all?" Private fields are primarily for encapsulation: a user of a a class shouldn't have to know the internals of that class' implementation. In fact, they shouldn't know, because if they relied on those specifics, then the implementer would