History

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McKeeman's XPL was a very significant development. Several commercial quality tools were developed with it, including several from Intel (then of PL/M fame) and Digital Research (then of CP/M fame).

The MSP parsing algorithm, while serviceable, is very restrictive.

However, as the commercial products can attest, it is still good enough for many applications, including complete languages such as XPL itself.

And, in an improved form, available from a user through his institution (use "XPL" as a search key, and you will find it), it is even more efficient than as-released by McKeeman in this book, although the improved form still uses the MSP algorithm.

Alas, parsing algorithms have been dramatically improved over the years, and in 1969 alone, the very year this book was first published, Frank DeRemer published his SLR(1) algorithm in his MIT PhD dissertation (which see).

I am advised that DeRemer later updated this XPL system to include an improved SLR(1) parser generator, but DeRemer later left his institution for other persuits. Perhaps UC-Santa Cruz, DeRemer's former institution, has a copy of the SLR(1) version in their files?

This book's title is taken from the XPL system's compiler generator, which is called "Analyzer" in all text references.

Taken in perspective, the XPL language in general, and this book in particular, in which the XPL language and its implementation is presented in great detail, including its source code, is historically important.