Abstract:
-calculus viewed as a programming language. Both theoretically as a
model of computation and practically as an idealized implementation, it has
set the tone for the subsequent development of abstract machines for
functional programming languages. However, and even though variants of the
SECD machine have been presented, derived, and invented, the precise
rationale for its architecture and modus operandi has remained elusive. In
this article, we deconstruct the SECD machine into a -interpreter,
i.e., an evaluation function, and we reconstruct -interpreters into
a variety of SECD-like machines. The deconstruction and reconstructions are
transformational: they are based on equational reasoning and on a combination
of simple program transformations--mainly closure conversion, transformation
into continuation-passing style, and defunctionalization.
The evaluation function underlying the SECD machine provides a precise rationale for its architecture: it is an environment-based eval-apply evaluator with a callee-save strategy for the environment, a data stack of intermediate results, and a control delimiter. Each of the components of the SECD machine (stack, environment, control, and dump) is therefore rationalized and so are its transitions.
The deconstruction and reconstruction method also applies to other abstract machines and other evaluation functions. It makes it possible to systematically extract the denotational content of an abstract machine in the form of a compositional evaluation function, and the (small-step) operational content of an evaluation function in the form of an abstract machine.
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