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 errorable data types from other languages, like error unions in Zig and Either in Haskell.
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 error handling.
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".