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This is another proofreading time remark. The new version of the EA
interpreter permits the use of two additional rule constructors. One is
the case constructor, like that in Pascal, which may make the execution
substantially more efficient. Of course, the same set of updates is
generated by a case command and its case-free equivalent; the difference is
in how fast this set is generated. For example, consider a sequence of
rules of the form ``if t=i
then
endif'' where
i ranges from 1 to a relatively large n. This example
is extreme, because the set {1,...,n}
of alternatives is so easy to deal with; but it is not
unusual to have similar long sequences of rules. In addition, the case
construct makes it easier to program a sequential execution of a sequence
of rules, which is sometimes desirable. The other rule constructor is
``let x=t in R'', which prevents re-evaluations of term 
in R and
which has been used informally. The let constructor was advocated by Raghu
Mani who is working on the new EA interpreter.