Add way to query absolute path for current directory?

[fingolfin]

For a script, I wanted to temporarily change the current working directory and later restore it. I naively thought I could use record the value of DirectoryCurrent(), then call ChangeDirectoryCurrent (from the IO package), and later restore to the stored path.

But that doesn't work, because DirectoryCurrent()always returns the same thing: dir("./").

I found no way to get the CWD, in particular no calls to getwd or getcwd in GAP or IO (well, GAP now has one in the internal function find_yourself, but that's not helpful).

There is GAPInfo.SystemEnvironment.PWD, but that isn't updated if ChangeDirectoryCurrent is called, so it's only helpful if no code before mine changed the CWD.

For now, I'll resort to using Process to executed pwd in a shell. But I really think we should add something here that does this in a more straightforward way.

BTW, I also noticed that @ChrisJefferson back in 2015 changed io to only defined ChangeDirectoryCurrent if it wasn't defined already -- my guess is in order to add this function to the GAP library. But that hasn't happened, has it?

[fingolfin]

I just released IO 4.5.4 which adds IO_getcwd. But I still think GAP should have something like this builtin.

[dimpase]

By the way, how does one extract "foo" from these dir("foo") created by DirectoryCurrent() and many other similar functions, e.g. DirectoriesPackagePrograms(...) ?

It's not documented, or at least is beyond my ability to find this in GAP docs.