However, in this context, do may have a completely different meaning, so until may not work properly. All these functions return the discarded fractional part as a secondary value.
The assumption was that you could develop a Lisp based application say, an expert system helping with jet turbine maintenance on some platform of choice and then deliver it to the Airforce on some rugged PC, where it would be used in some airbase.
The result was CLtL1. Lisp-1 refers to Scheme's model and Lisp-2 refers to Common Lisp's model. Doug Hoyte 's book Let Over Lambda extends the discussion on macros, claiming "Macros are the single greatest advantage that lisp has as a programming language and the single greatest advantage of any programming language.
Press, is a classic computer science text that uses Scheme to teach important programming concepts. Once you've found the bottleneck in your code, you can start tuning. The use of gensyms in a macro definition is a manual chore, but macros can be written which simplify the instantiation and use of gensyms.
Fully expanding a source form is called code walking.