[TxMt] Regular expression for current file name without extension

[Jan Jakob Bornheim]

Hello everybody,

I use TextMate mainly for LaTex editing.

In LaTex, I often use a package "jurarsp". This package works by way  
of running BibTex on a file with the extension *.rsp.aux (okay,  
admittedly the," rsp"-part is not the file extension, but you get the  
gist, I hope). In TextMate, I set all my LaTex projects to run the  
latex, bibtex, etc. commands on a master file.  Now I want to create a  
custom command that would run bibtex on the master_file.rsp.aux file,  
where the "master_file"-part would automatically be the name of the  
master file of the current project. The bibtex command already  
achieves this by using this simple syntax:

texMate.py bibtex 1

However, simply adding .rsp.aux after the 1 does not work. So I guess  
what I am looking for is a command or regular expression that would do  
the following: get the name of the current master file without  
extension, and add the extension .rsp.aux to this name. Maybe that is  
very simpe question I am asking but I promise you that I duly  
researched the mailing list and could not find an answer.

Thank you for any suggestions,

JJ