Note: This is MzScheme v360, which is what's packaged with Ubuntu Gutsy. I haven't had a chance to try PLT Scheme 4 yet, which by all accounts departs from the version 3 series considerably.

From the old PLT Scheme web page:

PLT Scheme is an umbrella name for a family of implementations of the Scheme programming language.

MzScheme is the lightweight, embeddable, scripting-friendly PLT Scheme implementation.

To reproduce my results on Ubuntu Gutsy Gibbon, install MzScheme with

sudo apt-get install mzscheme

and run the interpreter with

mzscheme --case-insens 2>&1

MzScheme makes the following choices:

- Allows the null combination, (), which returns the empty list. (more)
- Evaluates unquoted vectors to themselves. (more)
- Allows the 'sqrt' procedure to return exact results when able. (more)
- Allows the '*' procedure to return exact zero when a factor is an exact zero, even if other factors are inexact. (more)
- Allows the '/' procedure to return exact zero when the dividend is an exact zero, even if some divisors are inexact. (more)
- Allows division by inexact zero. (more)
- Supports arbitrary precision literal integers. (more)
- Supports arbitrary precision computed integers. (more)
- Supports the literal syntax for rational numbers (e.g. 1/2 is the literal number one half). (more)
- Supports the literal syntax for complex numbers (e.g. 1+i is the complex number with real and imaginary parts both 1). (more)
- Supports nontrivial exact rational numbers (e.g. (/ 1 3) produces an exact one third, not a floating point approximation). (more)
- Supports nontrivial exact complex numbers. (more)
- Guesses the denominators of inexact numbers per R5RS. (more)