However, the problem here is that I do not know how to replace all the "browser" appearances with "a" inside the andShow: block. I tried multiple variations like the one below, but I could not seem to get it to work as I want.
    replace: '`@browser showOn: `@target; from: `@origin; using: [         `@browser ``@.statements]' with: '`@browser transmit to: `@target; from: `@origin; andShow: [:a | a ``@.statements]';
Can anyone point me into the right direction?
Yes, you can put in the replacement code some code snippets like `{ :context | ... } Replace the "..." with some Smalltalk code that returns a parse tree node (or a collection of parse-tree nodes). The context-variable is a dictionary containing the current bindings of the matched nodes. So you can perform a sub-rewrite on ``@.statements to replace all accesses to `@browser with the variable a; and you return the transformed tree. Lukas -- Lukas Renggli www.lukas-renggli.ch