ECL supports all Common-Lisp data types exactly as defined in the ANSI. All functions and macros are expected to behave as described in that document and in the HyperSpec CLHS which is the online version of ANSI. This part of the book is simply a complement to those official documents and its role is to describes implementation dependent features, such as
Platform dependent limits.
Behavior which is marked as “implementation specific” in the standard.
Some corner cases which are not described in ANSI.
The philosophy behind certain implementation choices.
The following sections are organized following the structure in the online version of the standard CLHS: each chapter complements the one with the same name in the standard.