[syscall] Input

[ZackyGameDev]

Currently the UART component is already capable of reading bytes from input. however, i want it to be generalized into readline, readchar, etc type functions which are traditionally used to take user input in something liek C or rust std. something basic and minimal is fine. At the very least there should be a way to do readline.

thats for the kernel:: space

then, i wish there to be a syscall for user to also be able to take input.

the design itself is upto creative liberty. but it must be assigned syscall number 2. all inputs must be done using syscall number 2.

the pipeline is already laid out, all you need to do is define the input functions in kernel somewhere, then write syscalls from user to request kernel to use the kernel::input related functionality for the sake of the user. a buffer pointer, or something like that can be used for user to obtain the input taken by kernel. similar to how print works in reverse.

[tanishqdaiya]

Since we are going by K&R Terminology, here is a rough blueprint that I propose to implement:

kernel::getch() -> u8 returns a byte reading from uart directly.
kernel::getline(buf: &mut [u8]) -> usize reads characters until newline or buffer size reaches it limit and returns the number of bytes read.

I would like to ask though wether the getline should include the true input with the newline character or should I return a stripped result?

sys_readline(buf: &mut [u8]) -> usize will be implemented as a corollary name to sys_print.

[ZackyGameDev]

Looks pretty good to me. In typical C spirit I would prefer for \n to be included in readline.

[tanishqdaiya]

Just realized how idiotic Emacs formatting is. Should we setup a standardized formatter?

[ZackyGameDev]

Emacs? like, the text editor? whatever tools you use to implement the features is up to you. If im misunderstanding, please elaborate what you mean by a "formatter"

[tanishqdaiya]

A standardized formatter that can setup standards for fomatting our text. A popular example might be Prettier in the JS/TS world. Rust has rustfmt, we can setup a way to format the code to enforce specific preferences in code to encourage uniformity in the little things like tab widths, import discipline, max width, etc.

A story for another issue. You can always raise it from this little comment.

[ZackyGameDev]

Ah i see. I don't think anything like that is needed. However, throughout the project I have tried to be consistent with the formatting. Should you use any tools to align your code to the formatting used so far, it is up to you. If you wish to add any dotfiles or such to the project, it is up to you as well. Otherwise you can just be conscious of the formatting by looking at surrounding code in the old fashioned way.

[ZackyGameDev]

Solved by PR #10