I was looking for a solution where I can have a textual grammar for a DSL in order to specify filters on objects. I didn't really search the net because I know a cute little DSL for that already. It is called smalltalk, you might have heard of it. So what I do is putting the filter spec into the image via an http interface, materialize the filter in image and store it in a database to have them survive image restart. A filter spec could look like this [ :value | ( self sectionLabelOf: value ) = 'device' ] I want to know if there is any trouble to expect if I'm using plain block syntax for that task. As the blocks are injected using an http interface there is no environment/context problem. I would have some helper class as a facade to ease the filtering let's call it FilterHelper (would have a class side method #sectionLabelOf:) So getting the block code via HTTP I could do block := Smalltalk compiler evaluate: request contents for: FilterHelper logged: false And I would serialize it into a database as a string again doing self store: block sourceNode formattedCode Are there any possible drawbacks using it this way? thanks, Norbert