[wahern]

> Because they are not in a single scope

That all depends on the tool. Despite being cross-language (or rather, because of it), Ragel's source code-level interfaces don't require indirection through callbacks or function pointers. Ragel has a rich set of operators for embedding code blocks at transition points, operators for embedding expressions to control transitions, and operators for controlling how Ragel saves/restores state. You can organize your code nearly as freely as when open-coding a solution--a million little functions, a single gigantic function, or something in between.

The problem with many tools that are tightly integrated with a language--such as in-language AST manipulation, or via lambadas or closures--is that they're constrained by the expressiveness of the host language. You can see this with Lisp macros--you can trivially hack the s-expression tree to implement incredible semantic changes, but if the problem isn't best described using simple function (and specifically s-expression) syntax, then good luck identifying the semantics on inspection or understanding the implementation.