Question

This is a follow up to my previous question. It seems, unfortunately, that Chicken Scheme, by default, doesn’t support complex numbers, but rather offers a numbers egg that can be installed.

I have installed this egg, via chicken-install numbers, and I can load it in an interpreted environment. I can do this by calling use; either manually in the REPL, or by running my .scm file as a script through csi.

For example, this script works perfectly:

(use numbers)

(begin
  (display 3+3i)
  (newline)
)

when run with:

csi -s main.scm

But when I compile this exact same snippet with csc (even without any addtional flags), I get the same runtime error that I would if I didn’t load it (e.g. an unbound variable.) It seems as if in a compiled environment use doesn’t cut the mustard.

Two other things to note, is that, per the documentation, I tried other importing functions such as require-extension, require-library, etc., but none make an difference. The other is that if I change the name of the module to something other than numbers, say numberss, it fails to compile, complaining that it can’t load the extension, so obviously it is at least detecting that the numbers library is installed.

Could anyone please explain, preferably through a short working example how to use an egg in a compiled environment? Thanks in advance! 🙂

Answer 1

According to the helpful information provided by Peter Bex on the mailing list, most eggs will work out of the box, you simply need to use them.

Certain eggs though, provide extensions to the basic reader, and the compiler needs to be told about them. You can do this with the -X flag. As the documentation says, numbers is one of those packages.

Compiling your snippet with:

csc -X numbers-syntax main.scm

worked perfectly.

I hope this helps! 🙂