Scheme Implementation Choices (last updated September 2008) (what is this?) MIT Scheme Scheme 48 RScheme MzScheme Guile Bigloo Chicken Gambit Gauche Scm version 7.7.90.+ 1.3 0.7.3.4-b3u 360 1.8.1 2.8c 2.5 4.0 beta 20 0.8.8 5e3 null-combination true false false true false false true false true true r5rs-letrec false true false false true true false true false false case-sensitive false false true f