WIP: add one aditional module file for exercise support

src/cargo_toml.rs

@@ -108,6 +108,7 @@ mod tests {
             ExerciseInfo {
                 name: String::from("1"),
                 dir: None,
+                module_file: None,
                 test: true,
                 strict_clippy: true,
                 hint: String::new(),
@@ -116,6 +117,7 @@ mod tests {
             ExerciseInfo {
                 name: String::from("2"),
                 dir: Some(String::from("d")),
+                module_file: None,
                 test: false,
                 strict_clippy: false,
                 hint: String::new(),

src/info_file.rs

@@ -11,6 +11,9 @@ pub struct ExerciseInfo {
     pub name: String,
     /// Exercise's directory name inside the `exercises/` directory.
     pub dir: Option<String>,
+    /// Extra one Aditional Module file
+    #[serde(default)]
+    pub module_file: Option<String>,
     /// Run `cargo test` on the exercise.
     #[serde(default = "default_true")]
     pub test: bool,
@@ -52,6 +55,33 @@ impl ExerciseInfo {
 
         path
     }
+
+    pub fn module_file_path(&self) -> Option<String> {
+        if let Some(module_path) = &self.module_file {
+            let mut path = if let Some(dir) = &self.dir {
+                // 14 = 10 + 1 + 3
+                // exercises/ + / + .rs
+                let mut path = String::with_capacity(14 + dir.len() + module_path.len());
+                path.push_str("exercises/");
+                path.push_str(dir);
+                path.push('/');
+                path
+            } else {
+                // 13 = 10 + 3
+                // exercises/ + .rs
+                let mut path = String::with_capacity(13 + module_path.len());
+                path.push_str("exercises/");
+                path
+            };
+
+            path.push_str(&module_path);
+            path.push_str(".rs");
+
+            Some(path)
+        } else {
+            None
+        }
+    }
 }
 
 impl RunnableExercise for ExerciseInfo {