I've added plain TeX, and updated the original download link target so it is now C, C++, Perl and plain TeX. I'm quite sure that it is not possible to add PostScript, because there is no way to find a common starting for C, C++, Perl, plain TeX and PostScript. However, if we remove plain TeX, it is quite easy to add TCL and Bourne Shell (hint: TCL treats a backslash at the end of the comment line as an indicator that the comment continues in the next line). The starting line should be:
#define eval char *eval=