> All my DSL examples are in Ruby.
> 
> For DSL's, Ruby's syntax seems slightly more flexible than 
> Smalltalk (or maybe I just know how to abuse it more).
> 

Might I suggest that Smalltalk itself, isn't so much a language, as it is a
notation for creating DSL's.  Smalltalk for example, models predicate logic,
with simple objects and blocks, no special keywords such as
if/unless/do/while are necessary.  Ruby can't do this, and requires special
syntax in the language, due to its inability to pass multiple blocks and its
lack of Smalltalk style keyword selectors.  I'm curious where you see Ruby's
syntax being more flexible?