feat: improve `watch` execution mode

The `watch` command now requires user action to move to the next
exercise.

BREAKING CHANGE: this changes the behavior of `watch`.

51 files changed, 107 insertions, 0 deletions

diff --git a/exercises/enums/enums1.rs b/exercises/enums/enums1.rs
index 8b14f29..f490928 100644
--- a/exercises/enums/enums1.rs
+++ b/exercises/enums/enums1.rs
@@ -1,6 +1,8 @@
 // enums1.rs
 // Make me compile! Scroll down for hints!
 
+// I AM NOT DONE
+
 #[derive(Debug)]
 enum Message {
     // TODO: define a few types of messages as used below
diff --git a/exercises/enums/enums2.rs b/exercises/enums/enums2.rs
index 71ac839..8f04bd8 100644
--- a/exercises/enums/enums2.rs
+++ b/exercises/enums/enums2.rs
@@ -1,6 +1,8 @@
 // enums2.rs
 // Make me compile! Scroll down for hints
 
+// I AM NOT DONE
+
 #[derive(Debug)]
 enum Message {
     // TODO: define the different variants used below
diff --git a/exercises/enums/enums3.rs b/exercises/enums/enums3.rs
index c5d81bf..bb7dfb4 100644
--- a/exercises/enums/enums3.rs
+++ b/exercises/enums/enums3.rs
@@ -1,6 +1,8 @@
 // enums3.rs
 // Address all the TODOs to make the tests pass!
 
+// I AM NOT DONE
+
 enum Message {
     // TODO: implement the message variant types based on their usage below
 }
diff --git a/exercises/error_handling/errors1.rs b/exercises/error_handling/errors1.rs
index 8483234..a06f0ca 100644
--- a/exercises/error_handling/errors1.rs
+++ b/exercises/error_handling/errors1.rs
@@ -6,6 +6,8 @@
 // this function to have.
 // Scroll down for hints!!!
 
+// I AM NOT DONE
+
 pub fn generate_nametag_text(name: String) -> Option<String> {
     if name.len() > 0 {
         Some(format!("Hi! My name is {}", name))
diff --git a/exercises/error_handling/errors2.rs b/exercises/error_handling/errors2.rs
index 8b81207..315528f 100644
--- a/exercises/error_handling/errors2.rs
+++ b/exercises/error_handling/errors2.rs
@@ -16,6 +16,8 @@
 // There are at least two ways to implement this that are both correct-- but
 // one is a lot shorter! Scroll down for hints to both ways.
 
+// I AM NOT DONE
+
 use std::num::ParseIntError;
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
diff --git a/exercises/error_handling/errors3.rs b/exercises/error_handling/errors3.rs
index 31800fc..35cd5c3 100644
--- a/exercises/error_handling/errors3.rs
+++ b/exercises/error_handling/errors3.rs
@@ -3,6 +3,8 @@
 // `total_cost` function from the previous exercise. It's not working though!
 // Why not? What should we do to fix it? Scroll for hints!
 
+// I AM NOT DONE
+
 use std::num::ParseIntError;
 
 fn main() {
diff --git a/exercises/error_handling/errorsn.rs b/exercises/error_handling/errorsn.rs
index c2b16ce..cc90801 100644
--- a/exercises/error_handling/errorsn.rs
+++ b/exercises/error_handling/errorsn.rs
@@ -15,6 +15,8 @@
 //
 // Scroll down for hints :)
 
+// I AM NOT DONE
+
 use std::error;
 use std::fmt;
 use std::io;
diff --git a/exercises/error_handling/option1.rs b/exercises/error_handling/option1.rs
index c5a4a64..4e432a6 100644
--- a/exercises/error_handling/option1.rs
+++ b/exercises/error_handling/option1.rs
@@ -4,6 +4,8 @@
 // on `None`. Handle this in a more graceful way than calling `unwrap`!
 // Scroll down for hints :)
 
+// I AM NOT DONE
+
 pub fn pop_too_much() -> bool {
     let mut list = vec![3];
 
diff --git a/exercises/error_handling/result1.rs b/exercises/error_handling/result1.rs
index f9596e2..52972dc 100644
--- a/exercises/error_handling/result1.rs
+++ b/exercises/error_handling/result1.rs
@@ -1,6 +1,8 @@
 // result1.rs
 // Make this test pass! Scroll down for hints :)
 
+// I AM NOT DONE
+
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
 
diff --git a/exercises/functions/functions1.rs b/exercises/functions/functions1.rs
index 396dd56..b9312ae 100644
--- a/exercises/functions/functions1.rs
+++ b/exercises/functions/functions1.rs
@@ -1,6 +1,8 @@
 // functions1.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     call_me();
 }
diff --git a/exercises/functions/functions2.rs b/exercises/functions/functions2.rs
index 1cf95c3..c5b4418 100644
--- a/exercises/functions/functions2.rs
+++ b/exercises/functions/functions2.rs
@@ -1,6 +1,8 @@
 // functions2.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     call_me(3);
 }
diff --git a/exercises/functions/functions3.rs b/exercises/functions/functions3.rs
index b17543b..63bb586 100644
--- a/exercises/functions/functions3.rs
+++ b/exercises/functions/functions3.rs
@@ -1,6 +1,8 @@
 // functions3.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     call_me();
 }
diff --git a/exercises/functions/functions4.rs b/exercises/functions/functions4.rs
index 5baca0e..91f6295 100644
--- a/exercises/functions/functions4.rs
+++ b/exercises/functions/functions4.rs
@@ -4,6 +4,8 @@
 // This store is having a sale where if the price is an even number, you get
 // 10 (money unit) off, but if it's an odd number, it's 3 (money unit) less.
 
+// I AM NOT DONE
+
 fn main() {
     let original_price = 51;
     println!("Your sale price is {}", sale_price(original_price));
diff --git a/exercises/functions/functions5.rs b/exercises/functions/functions5.rs
index d9227c9..696edee 100644
--- a/exercises/functions/functions5.rs
+++ b/exercises/functions/functions5.rs
@@ -1,6 +1,8 @@
 // functions5.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let answer = square(3);
     println!("The answer is {}", answer);
diff --git a/exercises/if/if1.rs b/exercises/if/if1.rs
index 6da09d3..da77e35 100644
--- a/exercises/if/if1.rs
+++ b/exercises/if/if1.rs
@@ -1,5 +1,7 @@
 // if1.rs
 
+// I AM NOT DONE
+
 pub fn bigger(a: i32, b: i32) -> i32 {
     // Complete this function to return the bigger number!
     // Do not use:
diff --git a/exercises/macros/macros1.rs b/exercises/macros/macros1.rs
index a7c78a5..f7b89e0 100644
--- a/exercises/macros/macros1.rs
+++ b/exercises/macros/macros1.rs
@@ -1,6 +1,8 @@
 // macros1.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
diff --git a/exercises/macros/macros2.rs b/exercises/macros/macros2.rs
index bc2e56b..7fe9429 100644
--- a/exercises/macros/macros2.rs
+++ b/exercises/macros/macros2.rs
@@ -1,6 +1,8 @@
 // macros2.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     my_macro!();
 }
diff --git a/exercises/macros/macros3.rs b/exercises/macros/macros3.rs
index 84c4308..e9ef7f3 100644
--- a/exercises/macros/macros3.rs
+++ b/exercises/macros/macros3.rs
@@ -1,6 +1,8 @@
 // macros3.rs
 // Make me compile, without taking the macro out of the module! Scroll down for hints :)
 
+// I AM NOT DONE
+
 mod macros {
     macro_rules! my_macro {
         () => {
diff --git a/exercises/macros/macros4.rs b/exercises/macros/macros4.rs
index d844bb0..2893a15 100644
--- a/exercises/macros/macros4.rs
+++ b/exercises/macros/macros4.rs
@@ -1,6 +1,8 @@
 // macros4.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
diff --git a/exercises/modules/modules1.rs b/exercises/modules/modules1.rs
index 0e092c5..3f44968 100644
--- a/exercises/modules/modules1.rs
+++ b/exercises/modules/modules1.rs
@@ -1,6 +1,8 @@
 // modules1.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 mod sausage_factory {
     fn make_sausage() {
         println!("sausage!");
diff --git a/exercises/modules/modules2.rs b/exercises/modules/modules2.rs
index 3cfa36d..a3497cf 100644
--- a/exercises/modules/modules2.rs
+++ b/exercises/modules/modules2.rs
@@ -1,6 +1,8 @@
 // modules2.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 mod delicious_snacks {
     use self::fruits::PEAR as fruit;
     use self::veggies::CUCUMBER as veggie;
diff --git a/exercises/move_semantics/move_semantics1.rs b/exercises/move_semantics/move_semantics1.rs
index ab855fc..625096d 100644
--- a/exercises/move_semantics/move_semantics1.rs
+++ b/exercises/move_semantics/move_semantics1.rs
@@ -1,6 +1,8 @@
 // move_semantics1.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let vec0 = Vec::new();
 
diff --git a/exercises/move_semantics/move_semantics2.rs b/exercises/move_semantics/move_semantics2.rs
index f85b3ed..28749e2 100644
--- a/exercises/move_semantics/move_semantics2.rs
+++ b/exercises/move_semantics/move_semantics2.rs
@@ -1,6 +1,8 @@
 // move_semantics2.rs
 // Make me compile without changing line 10! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let vec0 = Vec::new();
 
diff --git a/exercises/move_semantics/move_semantics3.rs b/exercises/move_semantics/move_semantics3.rs
index 8b91896..a5b41b4 100644
--- a/exercises/move_semantics/move_semantics3.rs
+++ b/exercises/move_semantics/move_semantics3.rs
@@ -3,6 +3,8 @@
 // (no lines with multiple semicolons necessary!)
 // Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let vec0 = Vec::new();
 
diff --git a/exercises/move_semantics/move_semantics4.rs b/exercises/move_semantics/move_semantics4.rs
index 90930f0..b01e593 100644
--- a/exercises/move_semantics/move_semantics4.rs
+++ b/exercises/move_semantics/move_semantics4.rs
@@ -3,6 +3,8 @@
 // in `fn main`, we instead create it within `fn fill_vec` and transfer the
 // freshly created vector from fill_vec to its caller. Scroll for hints!
 
+// I AM NOT DONE
+
 fn main() {
     let vec0 = Vec::new();
 
diff --git a/exercises/primitive_types/primitive_types1.rs b/exercises/primitive_types/primitive_types1.rs
index c3d11fe..0912139 100644
--- a/exercises/primitive_types/primitive_types1.rs
+++ b/exercises/primitive_types/primitive_types1.rs
@@ -2,6 +2,8 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
+// I AM NOT DONE
+
 fn main() {
     // Booleans (`bool`)
 
diff --git a/exercises/primitive_types/primitive_types2.rs b/exercises/primitive_types/primitive_types2.rs
index f5c8f87..6576a4d 100644
--- a/exercises/primitive_types/primitive_types2.rs
+++ b/exercises/primitive_types/primitive_types2.rs
@@ -2,6 +2,8 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
+// I AM NOT DONE
+
 fn main() {
     // Characters (`char`)
 
diff --git a/exercises/primitive_types/primitive_types3.rs b/exercises/primitive_types/primitive_types3.rs
index 7ce2226..bf2716a 100644
--- a/exercises/primitive_types/primitive_types3.rs
+++ b/exercises/primitive_types/primitive_types3.rs
@@ -2,6 +2,8 @@
 // Create an array with at least 100 elements in it where the ??? is. 
 // Scroll down for hints!
 
+// I AM NOT DONE
+
 fn main() {
     let a = ???
 
diff --git a/exercises/primitive_types/primitive_types4.rs b/exercises/primitive_types/primitive_types4.rs
index e1ccdbc..e675aa1 100644
--- a/exercises/primitive_types/primitive_types4.rs
+++ b/exercises/primitive_types/primitive_types4.rs
@@ -2,6 +2,8 @@
 // Get a slice out of Array a where the ??? is so that the `if` statement
 // returns true. Scroll down for hints!!
 
+// I AM NOT DONE
+
 #[test]
 fn main() {
     let a = [1, 2, 3, 4, 5];
diff --git a/exercises/primitive_types/primitive_types5.rs b/exercises/primitive_types/primitive_types5.rs
index 0d53c9c..d8527ee 100644
--- a/exercises/primitive_types/primitive_types5.rs
+++ b/exercises/primitive_types/primitive_types5.rs
@@ -2,6 +2,8 @@
 // Destructure the `cat` tuple so that the println will work.
 // Scroll down for hints!
 
+// I AM NOT DONE
+
 fn main() {
     let cat = ("Furry McFurson", 3.5);
     let /* your pattern here */ = cat;
diff --git a/exercises/primitive_types/primitive_types6.rs b/exercises/primitive_types/primitive_types6.rs
index 854544f..8fe9a36 100644
--- a/exercises/primitive_types/primitive_types6.rs
+++ b/exercises/primitive_types/primitive_types6.rs
@@ -3,6 +3,8 @@
 // You can put this right into the `println!` where the ??? is.
 // Scroll down for hints!
 
+// I AM NOT DONE
+
 fn main() {
     let numbers = (1, 2, 3);
     println!("The second number is {}", ???);
diff --git a/exercises/standard_library_types/arc1.rs b/exercises/standard_library_types/arc1.rs
index d610e5f..effd28a 100644
--- a/exercises/standard_library_types/arc1.rs
+++ b/exercises/standard_library_types/arc1.rs
@@ -4,6 +4,8 @@
 // somewhere. Try not to create any copies of the `numbers` Vec!
 // Scroll down for hints :)
 
+// I AM NOT DONE
+
 use std::sync::Arc;
 use std::thread;
 
diff --git a/exercises/standard_library_types/iterators2.rs b/exercises/standard_library_types/iterators2.rs
index b6d3366..ea523e7 100644
--- a/exercises/standard_library_types/iterators2.rs
+++ b/exercises/standard_library_types/iterators2.rs
@@ -5,6 +5,8 @@
 // Step 3. Apply the `capitalize_first` function again to a list, but try and ensure it returns a single string
 // As always, there are hints below!
 
+// I AM NOT DONE
+
 pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
     match c.next() {
diff --git a/exercises/standard_library_types/iterators3.rs b/exercises/standard_library_types/iterators3.rs
index c012795..8fc57f2 100644
--- a/exercises/standard_library_types/iterators3.rs
+++ b/exercises/standard_library_types/iterators3.rs
@@ -8,6 +8,8 @@
 // a major hint.
 // Have fun :-)
 
+// I AM NOT DONE
+
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
     NotDivisible(NotDivisibleError),
diff --git a/exercises/standard_library_types/iterators4.rs b/exercises/standard_library_types/iterators4.rs
index 13613a6..39be8bf 100644
--- a/exercises/standard_library_types/iterators4.rs
+++ b/exercises/standard_library_types/iterators4.rs
@@ -1,5 +1,7 @@
 // iterators4.rs
 
+// I AM NOT DONE
+
 pub fn factorial(num: u64) -> u64 {
     // Complete this function to return factorial of num
     // Do not use:
diff --git a/exercises/strings/strings1.rs b/exercises/strings/strings1.rs
index 2e5088f..3335734 100644
--- a/exercises/strings/strings1.rs
+++ b/exercises/strings/strings1.rs
@@ -1,6 +1,8 @@
 // strings1.rs
 // Make me compile without changing the function signature! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let answer = current_favorite_color();
     println!("My current favorite color is {}", answer);
diff --git a/exercises/strings/strings2.rs b/exercises/strings/strings2.rs
index c77e16f..3890cfe 100644
--- a/exercises/strings/strings2.rs
+++ b/exercises/strings/strings2.rs
@@ -1,6 +1,8 @@
 // strings2.rs
 // Make me compile without changing the function signature! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let word = String::from("green"); // Try not changing this line :)
     if is_a_color_word(word) {
diff --git a/exercises/structs/structs1.rs b/exercises/structs/structs1.rs
index 138b3fd..6d0b2f4 100644
--- a/exercises/structs/structs1.rs
+++ b/exercises/structs/structs1.rs
@@ -1,6 +1,8 @@
 // structs1.rs
 // Address all the TODOs to make the tests pass!
 
+// I AM NOT DONE
+
 struct ColorClassicStruct {
     // TODO: Something goes here
 }
diff --git a/exercises/structs/structs2.rs b/exercises/structs/structs2.rs
index db381e7..0699137 100644
--- a/exercises/structs/structs2.rs
+++ b/exercises/structs/structs2.rs
@@ -2,6 +2,8 @@
 // Address all the TODOs to make the tests pass!
 // No hints, just do it!
 
+// I AM NOT DONE
+
 #[derive(Debug)]
 struct Order {
     name: String,
diff --git a/exercises/test1.rs b/exercises/test1.rs
index 6c27355..3e13ce5 100644
--- a/exercises/test1.rs
+++ b/exercises/test1.rs
@@ -7,6 +7,8 @@
 // more than 40 at once, each apple only costs 1! Write a function that calculates
 // the price of an order of apples given the order amount. No hints this time!
 
+// I AM NOT DONE
+
 // Put your function here!
 // fn ..... {
 
diff --git a/exercises/test2.rs b/exercises/test2.rs
index 7fe81c6..d01606c 100644
--- a/exercises/test2.rs
+++ b/exercises/test2.rs
@@ -7,6 +7,8 @@
 // you think each value is. That is, add either `string_slice` or `string`
 // before the parentheses on each line. If you're right, it will compile!
 
+// I AM NOT DONE
+
 fn string_slice(arg: &str) {
     println!("{}", arg);
 }
diff --git a/exercises/test3.rs b/exercises/test3.rs
index 9a72118..f94c36f 100644
--- a/exercises/test3.rs
+++ b/exercises/test3.rs
@@ -7,6 +7,8 @@
 // we expect to get when we call `times_two` with a negative number.
 // No hints, you can do this :)
 
+// I AM NOT DONE
+
 pub fn times_two(num: i32) -> i32 {
     num * 2
 }
diff --git a/exercises/test4.rs b/exercises/test4.rs
index e50f1b0..c543a64 100644
--- a/exercises/test4.rs
+++ b/exercises/test4.rs
@@ -5,6 +5,8 @@
 
 // Write a macro that passes the test! No hints this time, you can do it!
 
+// I AM NOT DONE
+
 fn main() {
     if my_macro!("world!") != "Hello world!" {
         panic!("Oh no! Wrong output!");
diff --git a/exercises/tests/tests1.rs b/exercises/tests/tests1.rs
index b11221f..1465e37 100644
--- a/exercises/tests/tests1.rs
+++ b/exercises/tests/tests1.rs
@@ -6,6 +6,8 @@
 // This test has a problem with it -- make the test compile! Make the test
 // pass! Make the test fail! Scroll down for hints :)
 
+// I AM NOT DONE
+
 #[cfg(test)]
 mod tests {
     #[test]
diff --git a/exercises/tests/tests2.rs b/exercises/tests/tests2.rs
index 6775d61..81e30e0 100644
--- a/exercises/tests/tests2.rs
+++ b/exercises/tests/tests2.rs
@@ -2,6 +2,8 @@
 // This test has a problem with it -- make the test compile! Make the test
 // pass! Make the test fail! Scroll down for hints :)
 
+// I AM NOT DONE
+
 #[cfg(test)]
 mod tests {
     #[test]
diff --git a/exercises/tests/tests3.rs b/exercises/tests/tests3.rs
index e10d2aa..af48095 100644
--- a/exercises/tests/tests3.rs
+++ b/exercises/tests/tests3.rs
@@ -3,6 +3,8 @@
 // the test passes. Then write a second test that tests whether we get the result
 // we expect to get when we call `is_even(5)`. Scroll down for hints!
 
+// I AM NOT DONE
+
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
 }
diff --git a/exercises/threads/threads1.rs b/exercises/threads/threads1.rs
index 7983668..d23553e 100644
--- a/exercises/threads/threads1.rs
+++ b/exercises/threads/threads1.rs
@@ -5,6 +5,8 @@
 // of "waiting..." and the program ends without timing out the playground,
 // you've got it :)
 
+// I AM NOT DONE
+
 use std::sync::Arc;
 use std::thread;
 use std::time::Duration;
diff --git a/exercises/variables/variables1.rs b/exercises/variables/variables1.rs
index 1cdd270..174ad80 100644
--- a/exercises/variables/variables1.rs
+++ b/exercises/variables/variables1.rs
@@ -1,6 +1,13 @@
 // variables1.rs
 // Make me compile! Scroll down for hints :)
 
+// About this `I AM NOT DONE` thing:
+// We sometimes encourage you to keep trying things on a given exercise,
+// even after you already figured it out. If you got everything working and
+// feel ready for the next exercise, you the `I AM NOT DONE` comment below.
+
+// I AM NOT DONE
+
 fn main() {
     x = 5;
     println!("x has the value {}", x);
diff --git a/exercises/variables/variables2.rs b/exercises/variables/variables2.rs
index a0b4a37..e3c3b76 100644
--- a/exercises/variables/variables2.rs
+++ b/exercises/variables/variables2.rs
@@ -1,6 +1,8 @@
 // variables2.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let x;
     if x == 10 {
diff --git a/exercises/variables/variables3.rs b/exercises/variables/variables3.rs
index 165a277..7e3fd93 100644
--- a/exercises/variables/variables3.rs
+++ b/exercises/variables/variables3.rs
@@ -1,6 +1,8 @@
 // variables3.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let x = 3;
     println!("Number {}", x);
diff --git a/exercises/variables/variables4.rs b/exercises/variables/variables4.rs
index 71ebf0f..33eca9e 100644
--- a/exercises/variables/variables4.rs
+++ b/exercises/variables/variables4.rs
@@ -1,6 +1,8 @@
 // variables4.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let x: i32;
     println!("Number {}", x);