Programs as data objects

This volume constitutes the proceedings of the Second Symposium on Programs asDataObjects(PADO-II),heldattheUniversityofAarhus,Denmark,onMay 21–23,2001. PADO-IIwascolocatedwiththeThirdInternationalWorkshopon Implicit Computational Complexity (ICC2001) and the Seventeenth Conference on the Mathematical Foundations of Programming Semantics (MFPS XVII). The?rstPADOwasorganizedbyHaraldGanzingerandNeilJones,in1985. This second symposium took place at the occasion of Neil Jones’s 60th birthday, andonhiswish,weorganizeditasaresearchevent. Thecallforpaperswas openandelicited30submissionsfrom12countries. Overall,145reviewswere collected,andbasedonthese,theprogramcommitteeselected14papersfor presentation. Withoneexception,eachsubmissionreceivedatleast4reviews. Whererelevant,atranscriptofthe(electronic)PCmeetingwasalsoenclosed.^ 1 PADO-IIwassponsoredbyBRICS andthe EspritWorkingGroupAPPSEM, and organized in cooperation with the European Association for Programming Languages and Systems (EAPLS) and the Special Interest Group on Progr- ming Languagesof the Association for Computing Machinery (ACM SIGPLAN). We gratefully acknowledge their support. We also extend our thanks to the PC members and e