Towards Partial Evaluation of Full Scheme

We present a binding-time analysis for Scheme which enables an ooine partial evaluator to successfully treat Scheme's reeective features eval, apply, and the control operator call/cc. Additionally, our analysis empowers the specializer to select the most eecient representation for each object. This removes some limitations of previous specializers regarding the use of higher-order functions. The theoretical development is backed by an implementation. features, meta-computation The programming language Scheme 20] is an ideal vehicle for meta-computation, speciically for partial evaluation. Part of the appropriateness of Scheme for meta-computation tasks derives from its reeective features: eval 27], which reeects the external representation of, say, a procedure to a functional value, apply, which reeects lists to argument lists, and call/cc 1 , which makes the continuation of the current expression available as a procedure. The continuation can be viewed as a reiied object from the meta-interpreter (supposedly written in CPS). Much work in partial evaluation has been done in the context of Scheme 3, 6, 7, 5, 8]. However, its reeective features have been neglected so far. In order to overcome this drawback, we present a binding-time analysis and a specialization algorithm for a large functional subset of Scheme. The subset includes eval, apply, and call/cc. Additionally, our new analysis supports vari-adic functions and includes a representation analysis which treats external and built-in operators more liberal than previous analyses. The latter analysis improves the eeciency of the specializer by enabling it to choose most eecient representations for functions and other partially static data. To the best of our knowledge , these features are unique to our work. Overview In the following section we brieey review ooine partial evaluation. We assume some familiarity with partial evaluation 21] and with type-based binding-time analysis (e.g., 15, 16, 18, 7]). In Sec. 2, we present two applications|parser generation and exception handling|which beneet from a partial evaluator capable of dealing with eval, apply, and call/cc. Section 3 informally explains the specializer's treatment of these reeective operators. In Sec. 4 we present the formal development of our binding-time analysis in a type-based framework. We brieey discuss automatic type reconstruction for the underlying type system in 1 Scheme calls it call-with-current-continuation. Partial evaluation is a program specialization technique which is based on aggressive constant propagation. The aim of specialization is improving eeciency: Given a source program and the static (known) part of its input , construct a residual program which …