Rewrite bin/init_exercise.py in Rust

.gitignore

@@ -5,4 +5,6 @@
 tmp
 bin/configlet
 bin/configlet.exe
-exercises/*/Cargo.lock
+bin/exercise
+bin/exercise.exe
+exercises/*/Cargo.lock

.travis.yml

@@ -11,6 +11,7 @@ script:
 - "./bin/configlet lint ."
 - "./_test/verify-exercise-difficulties.sh"
 - "./_test/check-exercises-for-authors.sh"
+- "sh ./_test/check-exercise-crate.sh"
 sudo: false
 rust:
   - stable

README.md

@@ -64,7 +64,7 @@ Please see the documentation about [adding new exercises](https://github.com/exe
 
 Note that:
 
-- The simplest way to generate a project template is to run `bin/init_exercise.py`. You'll need a Python installation >= 3.5 in order to run this script, but it will automate most of the following points for you.
+- The simplest way to generate, update or configure an exercise is to use the [exercise](https://github.com/exercism/rust/tree/master/util/exercise) utility provided in this repository. To compile the utility you can use the [bin/build_exercise_crate.sh](https://github.com/exercism/rust/tree/master/bin/build_exercise_crate.sh) script or, if the script does not work for you, use the `cargo build --release` command in the `util/exercise/` directory and then copy the `exercise` binary from the `util/exercise/target/release/` directory into the `bin/` directory. Use `bin/exercise --help` to learn about the existing commands and their possible usage. Please note that this utility depends on the `reqwest` crate and therefore you may need to install its [required libraries](https://github.com/seanmonstar/reqwest#requirements) (namely `openssl`) in your system.
 
 - Each exercise must stand on its own. Do not reference files outside the exercise directory. They will not be included when the user fetches the exercise.
 

_test/check-exercise-crate.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env sh
+
+# A script to ensure that the util/exercise crate builds after it was modified.
+
+EXERCISE_CRATE_PATH="util/exercise"
+
+CURRENT_BRANCH_NAME=$(git rev-parse --abbrev-ref HEAD)
+
+if [ "$CURRENT_BRANCH_NAME" != "master" ]; then
+    # Check the changes on the current branch against master branch
+    git diff --name-only master | grep "$EXERCISE_CRATE_PATH"
+else
+    # Check the commits on the master branch made during the week
+    # This is because Travis cron is set to test the master branch weekly.
+    git diff --name-only "@{7 days ago}" | grep "$EXERCISE_CRATE_PATH"
+fi
+
+if [ $? != 0 ]; then
+    echo "exercise crate was not modified. The script is aborted."
+
+    exit 0
+fi
+
+TRACK_ROOT="$(git rev-parse --show-toplevel)"
+
+if !(cd "$TRACK_ROOT/$EXERCISE_CRATE_PATH" && cargo check); then
+	echo "\nAn error has occurred while building the exercise crate.\nPlease make it compile."
+
+	exit 1
+else
+	echo "\nexercise crate has been successfully built."
+
+	exit 0
+fi

bin/build_exercise_crate.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+# Compile the 'exercise' crate and put it in the 'bin/' folder
+
+TRACK_ROOT="$(git rev-parse --show-toplevel)"
+
+EXERCISE_CRATE_PATH="$TRACK_ROOT/util/exercise"
+
+BIN_DIR_PATH="$TRACK_ROOT/bin"
+
+(
+	cd "$EXERCISE_CRATE_PATH"
+
+	echo "Building exercise crate"
+
+	cargo build --release
+
+	RELEASE_PATH="$EXERCISE_CRATE_PATH/target/release/exercise"
+
+	if [ -f "$RELEASE_PATH.exe" ]; then
+		RELEASE_PATH="$RELEASE_PATH.exe"
+	fi
+
+	echo "Copying exercise crate from $RELEASE_PATH into $BIN_DIR_PATH"
+
+	cp "$RELEASE_PATH" "$BIN_DIR_PATH"
+)