Ptom { a Pascal Translator for Mobile Code

We report on an implementation of a pascal translator that generates code for mobile software messengers (agents): these agents can roam a network of interconnected execution platforms on behalf of a user, enabling users to implement customized network functionality themselves. In this report we focus on the language extensions (pascal-m) and the implementation aspects of the translator. The main departure in pascal-m from standard pascal is that the programmer has access to the generated code in form of string constants. An interesting aspect of the \pascal-to-MM" (ptom) translator is that pascal-m is translated to the stack-based high-level language MM. MM is similar to postscript and has no notion of memory addresses although pascal compilers usually produce code for machines or software interpreters with word address-able memory: because MM completely hides the exact memory locations of code as well as data, we have to use other implementation approaches for activation frames, variable dereferencing and code xups. Other aspects of the translator implementation like data mapping and heap management are also described. Finally, we relate our work to recent developments in the eld of intermediate code and languages.