Perhaps the best way to do that is to build a pseudo compiler/decompiler. You would have to parse the Basic code building the tree. After that you would have to decompile that tree in Perl source. It is a hard project and perhaps will consume an man-time effort and surely a expertise in computer theory that will not payback. Besides it will probably generate a not optimized perl code, unless you spend another bucket of compiler optimization wizardry over it. The rewrite from scratch seems to be a better approach.