This paper describes our first step towards the integration of partial
evaluation into standard interpretation. The two main issues in this
integration are the treatment of heap objects and side-effects. To
enable specialization with respect to the heap objects that are
allocated beforehand in standard evaluation, specialization is
performed with respect to the heap state at specialization time rather
than based on a program text input so far. To avoid duplication of
heap objects, direct references to heap objects are allowed in the
specialized programs, in addition to the use of the conventional
let-insertion technique. Despite our modest approach on side-effects
that we allow partial evaluation of only side-effect free portions of
a program, the resulting system covers some typical cases, such as the
use of partial evaluation during an interactive debugging session. It
also enables us to specialize a (side-effect free) program with
respect to cyclic data structures, which was not easy before. We
formalize this integration using store semantics and state its
correctness. The system is implemented in Scheme and various examples
are tested. Among them, we show specialization of a ray tracing
program.
