We present a framework of an online partial evaluator for a callby -value -calculus with destructive updates of data structures. It properly and correctly specializes expressions that contain sideeffects, while preserving pointer equality, which is an important property for programs using updates. Our partial evaluator uses a side-effect analysis to extract immutable data structures and then performs an online specialization using preactions. Once mutable and immutable data structures are separated, partial evaluation is done in sucha way that accessesto immutable ones are performed at specialization time, while accessesto mutable ones are residualized. For the correct residualization of side-effecting operations, preactions are used to solve various issues, including code elimination, code duplication, and execution order preservation. The preaction mechanism also enablesus to reduceexpressionsthat were residualized when the conventional let-expression approach of Similix was used. Th...

This paper presents an online partial evaluator with a mechanism to handle I/O-type side-effects using preactions, and reports our experiment of using the partial evaluator as a compiler for the reflective language Black we are designing. Black is a Scheme-based reflective language, which allows user programs to access and modify its metalevel interpreter (or the language semantics) from within the same language framework. Because the semantics may change during computation, it is impossible to compile using a conventional Scheme compiler. To cope with this flexibility, we implemented an online partial evaluator, and specialized a Scheme meta-circular interpreter with respect to a modified interpreter to obtain an efficient version of the modified interpreter. The resulting interpreter turns out to be quite efficient in that it is almost identical to the original Scheme interpreter, except that it correctly reflects the modification made by users. In fact, we got more: by supplying a s...