Common Lisp CLISP

Common Lisp is
  * a convential programming language and an AI language
  * interactive
  * a Lisp for professional use

Common Lisp CLISP
  * needs only 2 MB of memory
  * implements 99% of the CLtL1 standard, as well as some extensions
  * can call your preferred editor
  * is freely distributable

Common Lisp CLISP provides
  * an interpreter
  * a compiler which makes execution of programs 5 times faster
  * all data types with unlimited size (the size need never be declared,
    the size of lists and arrays may be changed dynamically)
  * integers of arbitrary length, unlimited floating point number precision
  * 594 library functions, 542 of them written in C