solution is a helper to generate solution of exercise

Quick start

cargo add solution

Add a solution feature in your crate.

[package]
name = "exo01"

[features]
solution = []

[dependencies]
solution = { version = "0.1.0" }

And use solution!() and/or solution_type macro, e.g.:

use solution::{solution,solution_type};

/// this struct should be removed
struct WhichType;

fn variable_strip_prefix(string: solution_type!(&str)) -> Option<solution_type!(WhichType => &str)> {
  solution!({
    string.strip_prefix("$")
  })
}

fn main() {
  for arg in std::env::args().skip(1) {
    solution!(hint = "remove the optionnal '$' at start and display environment variable", {
      let name = variable_strip_prefix(&arg).unwrap_or(&arg);
      println!("{name} = {}", std::env::var(name).expect("404 variable not found"));
    })
  }
}

Now you can build student version with cargo build (but depends which you have write in solution_type!() it can be unable to build) and teacher version with cargo build -F solution.

Generate student version

cargo install solution_cli
solution --source <teacher_directory> generate <student_directory>

The last command generate new rust file in <student_directory> :

use solution::{solution,solution_type};

/// this struct should be removed
struct WhichType;

fn variable_strip_prefix(string: /* TODO:  */ _) -> Option</* TODO:  */ WhichType> {
  todo!()
}

fn main() {
  for arg in std::env::args().skip(1) {
    todo!("remove the optionnal '$' at start and display environment variable")
  }
}