--keep-generated-signatures (and -incremental must be on too). This outputs a generated-signatures directory in your source tree filled with .sig files (named using the package structure, delimited by underscores: mx_core_Foo.sig). These are all the AS files that were compiled and/or synthesized in-memory (e.g. from [Embed] metadata) by MXMLC.So, now you have a list of AS files that were compiled. Now we need a list of files that we have.
cd to your source directory (if you have more than one, you're on your own):$ cd src/
$ diff <(find . -name "*.as"|sed 's@\./@@'|sort) <(find generated-signatures -name "*.sig"|sed 's@generated-signatures/@@'|sed 's@_@/@g'|sed 's@\.sig@.as@'|sort)|grep "<"|sed 's@< @@'
This should give you a list of files that do not have signatures in the compiler, and should be safe to remove.
For the curious:
.sig files are public class signatures -- they are a canonically ordered list of every function, field, import, metadata, etc., that could potentially have a dependency, in either direction, on another class being compiled. One way I used this was for an optimization to determine if a class' dependencies need to be recompiled or not -- if the signature didn't change, they don't. Every AS class gets a signature generated -- on the extremely rare case where a signature can't be generated (due to unforseen syntax or something), a warning is printed with mini-stacktrace to the console -- if you don't see that, you can be sure it's complete.
