Programmable formatting of program text

Abstract

EXTENDED ABSTRACTThe T~MPR System originated as an approach to the problem of sutomating the routine modifications of Fortran source programs required to adapt them to a variety of uses or environments [I]**. Overall, the system accomplishes such modifications by applying transformations to Fortran programs at the source level. But the process differs markedly, in detail, from string-based editing or macro expansion. Three steps are involved: (I) A Fortran source program is processed by the TA~R Recogoizer, yielding essentially a parse tree called the abstract form. (2) The Transformation Interpreter applies ZGT's (Intragrammatlcal Transformations) to the abstract form as tree operations [2]. (3) The abstract form is then reconverted to source program form by the Formatter. By ensuring that the transformations are applied only to the correct syntactic entities and only in the intended contexts, the use of the abstract form greatly slmpllf~es establishing the reliability of the overall process.The Formatter, of course, is responsible for meeting the requirements of the target lansuage, such as use of blanks, statement continuations, etc. In addition, the formatting process is charged with imparting to the resultant program a certain degree of styl e. Areas of concern here are spacing between sy~nbols, choosing "logical" breakpoints in multi~llne statements, and, at a higher level, con~nentlng and indentation to help reveal