Transparent files in APL (A Preliminary Proposal)
Jim Lucas · ACM SIGAPL APL Quote Quad · 1982
File-related operations in APL could be classified according to whether manipulation of the file is restricted solely to APL or whether the file is to be accessible via another language. In the latter case communication is often dependent on the other language and should not affect APL language design, except for the provision of a general facility. Guidelines for using shared variables and defined functions to this end are presented. Files strictly intra-APL can and should be independent of such external communication, and a detailed proposal is presented whereby such internal files can be viewed and manipulated as if they were ordinary variables. The same conventions could also be extended to cover named objects in the workspace, thus giving enhanced access control within the workspace. Concerns addressed include syntax and nomenclature for reference to controlled or extra-workspace named objects, space constraints, error classification and reporting, upward compatibility, and to some extent, implementation concerns.