[Colloq] PhD Thesis Proposal - David Herman - Thursday, January 17

[Rachel Kalweit]

College of Computer and Information Science

presents
PhD Thesis Proposal by:
David Herman

Proposal Title:
A Theory of Hygienic Macros

Thursday, January 17, 2008
3:00pm
366 West Village H

Abstract:
Hygienic macro systems, such as Scheme's, automatically rename variables to prevent unintentional variable capture. The experience of the practical programmer is that hygienic macros "just work." Yet hygiene has never been formally presented as a specification rather than an algorithm. According to folklore, the definition of hygienic macro expansion hinges on the preservation of alpha-equivalence.  But the only known notion of alpha-equivalence for programs with macros depends on the results of macro expansion! In this work, I break this circularity by introducing explicit binding specifications into the syntax of macro definitions, thereby permitting a definition of alpha-equivalence independent of expansion.

I have defined a semantic model for hygienic macro expansion and provided the first formal definition of hygiene as a correctness criterion for such a semantics. The current semantics models a first-order subset of Scheme-like macros and is provably hygienic. The remainder of my dissertation work will consist primarily of extending this formalism to handle more expressive constructs such as recursive and higher-order macros (i.e., "macro-defining macros").

Committee:
Mitchell Wand (advisor)
William D. Clinger
Olin Shivers
Oleg Kiselyov (Fleet Numerical Meteorology and Oceanography Center)