A UDC should not be dependent on other functions and global variables in WS. AplFile is not perfect in that sense, because it uses a few supporting functions. I've tried to keep this to a minimum and only functions which I consider "well known" and used more or less as primitives are used.
AplFile makes it possible to use OOP techniques on files. Since almost all objects in APL+Win (at present time) are visible objects and there are no "data" objects, AplFile has to be based on a visible object. I've selected the "Frame" class as a container for the file object. This frame has its visible property set to 0, so the object will not show up on a form. AplFile has most of the F system functions and variables implemented as methods and properties, but also has useful new features and extensions to the F functions.
Please send suggestions and comments regarding AplFile to
S-506 30 Boras