Converting to scheme/base. Adding atomic renaming of compiled zos. Simplifying some parts with library functions. Using a low-tech continuation barrier, re: robby. Using define to reduce left creep. Adding commentary on design choices. Tested on Linux and Mac OS X. Based on code from Petey Aldous.
Converting to scheme/base. Adding atomic renaming of compiled zos. Simplifying some parts with library functions. Using a low-tech continuation barrier, re: robby. Using define to reduce left creep. Adding commentary on design choices. Tested on Linux and Mac OS X. Based on code from Petey Aldous.

svn: r17166

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket