[plt-scheme] Examples of language implementation

BTW, the language you cited is now at:  http://www.neilvandyke.org/sicp-plt/

One key file of that, concerning DrScheme, was adapted from one in the 
EoPL language.  It probably also stole some incantations from the R5RS 
support.  Some documentation (perhaps including the manual now called 
"Plugins: Extending DrScheme"?) was used.  Some other things were 
figured out through time-consuming experimentation.  Most of the 
trickiness was specific to producing a language that is mostly R5RS with 
a few differences.