Imperative Expressions using Implicit Environments

In PFL – an experimental process functional programming language [5, 6, 7] the imperative computation and the functional evaluation are clearly separated in a well-balanced manner. Neither environment variables nor assignments are used in PFL expressions that still manipulate the state using both explicit and implicit environments. In this way PFL extends to both imperative and functional languages, preserving the ability for reasoning about the programs [9, 10] and systems [3, 4] in terms of expressions. In this paper we concentrate to expressing the imperative programs in a purely functional manner using just implicit environments, which is semantically equivalent to that used in imperative functional languages [11]. However, the implicit environment in PFL is visible, providing the strong feedback about the implementation to a user.