🚀 go-pugleaf

I am trying to translate from one format for expressions (Theorist) to
another (LaTeX).  I can almost specify the translation as a list of
sed regular expression replace commands.  The only problem is with
replacing something like "(A#B	C	D)" with "\product_{B=C}^{D}A",
where A, C, and D are arbitrary expressions, and so could potentially
contain the delmiter (tab) that separates fields in Theorist's
version of the product.

So, what I want is to be able to specify the substitution as something
like "\(\X\)#\(\w*\)	\(\X\)	\(\X\))" => "\\product_{\2=\3}^{\4}\1", 
where \X matches any s-expression.

Does anybody have utilities for doing such a thing?

Thanks.

-- Ethan