Does Chicken Scheme support complex numbers? If so, why am I getting this error?

问题

I just started learning a little Scheme, and I'm using Dorai Sitaram's Teach Yourself Scheme in Fixnum Days. In said work it is stated:

Scheme numbers can be integers (eg, 42) ... or complex (2+3i).

Emphasis mine. Note the form.

Using the principles I had been taught so far I tried writing a few different programs that dealt with the different kinds of numbers. I ended up writing this extremely simple snippet to test complex numbers:

(begin
  (display 3+4i)
  (newline)
)

Testing this on codepad.org (which uses MzScheme) and Ideone.com (which uses guile) worked perfectly.

Now, when I tried it with Chicken Scheme (my local development environment), it compiles fine, but when run, crashes and gives me the error:

Error: unbound variable: 3+4i

  Call history:

  main.scm:2: 3+4i      <--

Apperently there's an unbound variable error, but with my limited Scheme I don't even know what that means (yet.)

Has anyone else experienced this? I know Chicken Scheme is supposed to be pretty standards compliant, and so it seems wierd that it wouldn't support something simple like this. I Googled through their documentation, but I couldn't find anything specific (although I think there is an external complex number library available, so perhaps that's a hint.)

If anyone has any suggestions, they'd be greatly appreciated. Thanks in advance! :)

回答1:

I believe you need to install the numbers extension for dealing with complex numbers in Chicken Scheme. Do this:

> chicken-install numbers

And don't forget to load it:

(use numbers)

来源：https://stackoverflow.com/questions/13504853/does-chicken-scheme-support-complex-numbers-if-so-why-am-i-getting-this-error