(Scheme In One Defun or Scheme In One Day) A small Scheme implementation in C by George Carrette. SIOD is arranged as a set of subroutines that can be called from any main program for the purpose of introducing an interpreted extension language. It compiles to 20 kbytes of executable (VAX/VMS). Lisp calls C and C calls Lisp transparently. SIOD supports symbols, strings, arrays, hash coding, file i/o (binary, text, seek), data save/restore in binary and text, interface to commercial databases such Oracle and Digital RDB. Version 3.0 runs on VAX/VMS,Unix, Sun-3, Sun-4, Amiga, Macintosh, MIPS, Cray, ALPHA/VMS, Windows NT and OS/2. It can be compiled by most ANSI C compilers and C++ compilers, e.g. gcc -Wall.