GNU APL ⎕FIO abstraction library.
TL;DR - ⎕FIO is too low-level IMO for use in APL and this library is my highly-biased reimagining of it.
See the library file fio.apl for more details.
In GNU APL, interations with the operating system (file handling, spawning processes, opening ports, etc.) are done with ⎕FIO. However, I find that there are several problems with it.
Prior to version GNU APL 1.9, ⎕FIO functions were specified with an axis argument, i.e. ⎕FIO[3] (fopen,) which lead to code that was hard to read. Now you can specify them by name, i.e. ⎕FIO['fopen'] or ⎕FIO.fopen. This is the reason I orignally developed this library, but there are still other things for which I think this library has value.
The ⎕FIO functions are replicas of C functions, whose error handling methods vary considerably between functions. This is fine in C, but APL is far more abstract than C with a completely different way to represent logic. This library provides, what I consider, to be a more consistent and sensible error handling scheme through the use of a vector that replicates the optional data type from other languages, like ? in Zig or std::optional in C++.
Many of the functions that handle file descriptors throw an exception on an unopened file descriptor, instead of returning some kind of error code. I think that this is kind of weird, and I have replaced it with the aforementioned optionals.
Some of the functions are also annoying to use. For example, ⎕FIO[20], mkdir, requires the file permissions to be converted from octal to decimal numbers before calling. Functions such as these are given a more user-friendly interface.
Additionally, this library provides a number of extra functions you will probably like, such as recursively creating and deleting directories.
Note: functions have been added as-needed, so it will not cover everything in ⎕FIO.
Dependencies:
- GNU APL: (https://www.gnu.org/software/apl)
There is a flake.nix you can use with nix develop to generate a development
enviroment.
Then, run one of the following commands:
apl --script test.apl
./test.apl- Add all functions from ⎕FIO.
- Fixed FIO∆READ_FD not reading from given file descriptor.
- Fixed FIO∆READ_ENTIRE_FD not properly returning read data.
- Swapped arugments for dyadic functions that work with file descriptors for a better user experience.
- Added FIO∆PRINT_FD and FIO∆PRINT for easily outputting strings without needing to convert them to bytes first.
- Renamed FIO∆FPRINTF -> FIO∆PRINTF_FD.
- Changed meta for unwrapping optionals from "↑O[2]" to "↑1↓V".