My 1987 book is now out of print, but it is available here in its entirety in PDF form, in one of two formats:

Both are fully searchable, thanks to OCR and Norman Ramsey.

Errata

Section 5.2.4, p87. We need an extra rule

match us [] E = E

This accounts for the possibility that in the constructor rule (Section 5.2.4) there may be some non-nullary constructors for which there are no equations.