optimizations up to section 5.8

README.md

@@ -11,9 +11,14 @@ pure Prolog.
 Pure Prolog is implemented as a simple REPL. "Pure Prolog" is Prolog
 without cut, meta- or extra-logical operators, or side effects of any
 kind. In terms of the tutorial pacing, the work has progressed to the
-to the end of section 5.6, skipping past 5.4. Atoms and lists are the
+to the end of section 5.7, skipping past 5.4. Atoms and lists are the
 only two data types currently supported.
 
+While proper environment trimming code is emitted by the code
+generator, it has no effect on the bytecode WAM, which lacks
+fine-grained control over the alignment and allocation of stack
+frames.
+
 ## Tutorial
 To enter a multi-clause predicate, the brackets ":{" and "}:" are used
 as delimiters. They must be entirely contained with their own lines.