ACL2 is a theorem prover for a purely functional subset of Common Lisp. It inherits Common Lisp’s unhygienic macros, which are used pervasively to eliminate repeated syntactic patterns. The lack of hygiene means that macros do not automatically protect their producers or consumers from accidental variable capture. This paper demonstrates how this lack of hygiene interferes with theorem proving....

Over the past two decades, Scheme macros have evolved into a powerful API for the compiler front-end. Like Lisp macros, their predecessors, Scheme macros expand source programs into a small core language; unlike Lisp systems, Scheme macro expanders preserve lexical scoping, and advanced Scheme macro systems handle other important properties such as source location. Using such macros, Scheme pro...

One of the base concepts of object-oriented programming is that of " method ". In languages supporting inheritance, this concept is realized by three different actions: (i) the introduction of a new method; (ii) the implementation/override of an existing method; (iii) the method call. The bindings between (ii) and (i), and between (iii) and (i) are typically based on method names, which are not...

We study the important problem of how a supplier should optimally share the consequences of demand uncertainty (i.e., the cost of inventory excesses and shortages) with a retailer in a two-level supply chain facing a finite planning horizon. In particular, we characterize a multiperiod contract form, the promised lead-time contract, that reduces the supplier’s risk from demand uncertainty and t...

It is known that the essential ingredients of a Lisp-style unhygienic macro system can be expressed in terms of advanced hygienic macro systems. We show that the reverse is also true: We present a model of a core unhygienic macro system, on top of which a hygiene-compatible macro system can be built, without changing the internals of the core macro system and without using a code walker. To ach...

Structured architecture would improve the systems quality by establishing discipline, but does not account of their evolution. We need to go beyond by discovering and using the hidden laws of urbanism that are intimately tied to autonomy, adaptation and evolution notions.

The rapid growth of the built environment has been pointed out as one of the major challenges to sustainability in the US. Low density “sprawling” neighborhoods represent the most undesired form of urban growth both for the waste of land and energy they cause, as well as for the lack of a “sense of place” they promote among their inhabitants. Several critiques to such type of urbanization have ...