Revert removing deprecated exercises

config.json

@@ -4,11 +4,8 @@
   "blurb": "Rust is a compiled programming language designed for speed, concurrency, and memory safety. Rust programs can run almost anywhere, from low-power embedded devices to web servers.",
   "foregone": [
     "binary",
-    "hexadecimal",
-    "nucleotide-codons",
     "octal",
-    "trinary",
-    "two-fer"
+    "trinary"
   ],
   "exercises": [
     {
@@ -1069,6 +1066,36 @@
       "topics": [
         "parser_reimplementation"
       ]
+    },
+    {
+      "slug": "two-fer",
+      "uuid": "c6631a2c-4632-11e8-842f-0ed5f89f718b",
+      "core": false,
+      "unlocked_by": null,
+      "difficulty": 1,
+      "topics": [
+        "match",
+        "strings"
+      ],
+      "deprecated": true
+    },
+    {
+      "slug": "nucleotide-codons",
+      "uuid": "8dae8f4d-368d-477d-907e-bf746921bfbf",
+      "core": false,
+      "unlocked_by": null,
+      "difficulty": 0,
+      "topics": null,
+      "deprecated": true
+    },
+    {
+      "slug": "hexadecimal",
+      "uuid": "496fd79f-1678-4aa2-8110-c32c6aaf545e",
+      "core": false,
+      "unlocked_by": null,
+      "difficulty": 0,
+      "topics": null,
+      "deprecated": true
     }
   ]
 }

exercises/hexadecimal/.gitignore

@@ -0,0 +1,8 @@
+# Generated by Cargo
+# will have compiled files and executables
+/target/
+**/*.rs.bk
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here http://doc.crates.io/guide.html#cargotoml-vs-cargolock
+Cargo.lock

exercises/hexadecimal/Cargo.toml

@@ -0,0 +1,3 @@
+[package]
+name = "hexadecimal"
+version = "0.0.0"

exercises/hexadecimal/README.md

@@ -0,0 +1,88 @@
+# Hexadecimal
+
+Convert a hexadecimal number, represented as a string (e.g. "10af8c"), to its decimal equivalent using first principles (i.e. no, you may not use built-in or external libraries to accomplish the conversion).
+
+On the web we use hexadecimal to represent colors, e.g. green: 008000,
+teal: 008080, navy: 000080).
+
+The program should handle invalid hexadecimal strings.
+
+## Rust Installation
+
+Refer to the [exercism help page][help-page] for Rust installation and learning
+resources.
+
+## Writing the Code
+
+Execute the tests with:
+
+```bash
+$ cargo test
+```
+
+All but the first test have been ignored. After you get the first test to
+pass, open the tests source file which is located in the `tests` directory
+and remove the `#[ignore]` flag from the next test and get the tests to pass
+again. Each separate test is a function with `#[test]` flag above it.
+Continue, until you pass every test.
+
+If you wish to run all tests without editing the tests source file, use:
+
+```bash
+$ cargo test -- --ignored
+```
+
+To run a specific test, for example `some_test`, you can use:
+
+```bash
+$ cargo test some_test
+```
+
+If the specific test is ignored use:
+
+```bash
+$ cargo test some_test -- --ignored
+```
+
+To learn more about Rust tests refer to the [online test documentation][rust-tests]
+
+Make sure to read the [Modules](https://doc.rust-lang.org/book/ch07-02-modules-and-use-to-control-scope-and-privacy.html) chapter if you
+haven't already, it will help you with organizing your files.
+
+## Further improvements
+
+After you have solved the exercise, please consider using the additional utilities, described in the [installation guide](https://exercism.io/tracks/rust/installation), to further refine your final solution.
+
+To format your solution, inside the solution directory use
+
+```bash
+cargo fmt
+```
+
+To see, if your solution contains some common ineffective use cases, inside the solution directory use
+
+```bash
+cargo clippy --all-targets
+```
+
+## Submitting the solution
+
+Generally you should submit all files in which you implemented your solution (`src/lib.rs` in most cases). If you are using any external crates, please consider submitting the `Cargo.toml` file. This will make the review process faster and clearer.
+
+## Feedback, Issues, Pull Requests
+
+The [exercism/rust](https://github.com/exercism/rust) repository on GitHub is the home for all of the Rust exercises. If you have feedback about an exercise, or want to help implement new exercises, head over there and create an issue. Members of the rust track team are happy to help!
+
+If you want to know more about Exercism, take a look at the [contribution guide](https://github.com/exercism/docs/blob/master/contributing-to-language-tracks/README.md).
+
+[help-page]: https://exercism.io/tracks/rust/learning
+[modules]: https://doc.rust-lang.org/book/ch07-02-modules-and-use-to-control-scope-and-privacy.html
+[cargo]: https://doc.rust-lang.org/book/ch14-00-more-about-cargo.html
+[rust-tests]: https://doc.rust-lang.org/book/ch11-02-running-tests.html
+
+## Source
+
+All of Computer Science [http://www.wolframalpha.com/examples/NumberBases.html](http://www.wolframalpha.com/examples/NumberBases.html)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

exercises/hexadecimal/example.rs

@@ -0,0 +1,33 @@
+fn parse_hex_digit(c: char) -> Option<i64> {
+    match c {
+        '0' => Some(0),
+        '1' => Some(1),
+        '2' => Some(2),
+        '3' => Some(3),
+        '4' => Some(4),
+        '5' => Some(5),
+        '6' => Some(6),
+        '7' => Some(7),
+        '8' => Some(8),
+        '9' => Some(9),
+        'a' => Some(10),
+        'b' => Some(11),
+        'c' => Some(12),
+        'd' => Some(13),
+        'e' => Some(14),
+        'f' => Some(15),
+        _ => None,
+    }
+}
+
+pub fn hex_to_int(string: &str) -> Option<i64> {
+    let base: i64 = 16;
+
+    string
+        .chars()
+        .rev()
+        .enumerate()
+        .fold(Some(0), |acc, (pos, c)| {
+            parse_hex_digit(c).and_then(|n| acc.map(|acc| acc + n * base.pow(pos as u32)))
+        })
+}

exercises/hexadecimal/src/lib.rs

@@ -0,0 +1,33 @@
+fn parse_hex_digit(c: char) -> Option<i64> {
+    match c {
+        '0' => Some(0),
+        '1' => Some(1),
+        '2' => Some(2),
+        '3' => Some(3),
+        '4' => Some(4),
+        '5' => Some(5),
+        '6' => Some(6),
+        '7' => Some(7),
+        '8' => Some(8),
+        '9' => Some(9),
+        'a' => Some(10),
+        'b' => Some(11),
+        'c' => Some(12),
+        'd' => Some(13),
+        'e' => Some(14),
+        'f' => Some(15),
+        _ => None,
+    }
+}
+
+pub fn hex_to_int(string: &str) -> Option<i64> {
+    let base: i64 = 16;
+
+    string
+        .chars()
+        .rev()
+        .enumerate()
+        .fold(Some(0), |acc, (pos, c)| {
+            parse_hex_digit(c).and_then(|n| acc.map(|acc| acc + n * base.pow(pos as u32)))
+        })
+}

exercises/hexadecimal/tests/hexadecimal.rs

@@ -0,0 +1,60 @@
+extern crate hexadecimal;
+
+#[test]
+fn test_hex_1_is_decimal_1() {
+    assert_eq!(Some(1), hexadecimal::hex_to_int("1"));
+}
+
+#[test]
+#[ignore]
+fn test_hex_c_is_decimal_12() {
+    assert_eq!(Some(12), hexadecimal::hex_to_int("c"));
+}
+
+#[test]
+#[ignore]
+fn test_hex_10_is_decimal_16() {
+    assert_eq!(Some(16), hexadecimal::hex_to_int("10"));
+}
+
+#[test]
+#[ignore]
+fn test_hex_af_is_decimal_175() {
+    assert_eq!(Some(175), hexadecimal::hex_to_int("af"));
+}
+
+#[test]
+#[ignore]
+fn test_hex_100_is_decimal_256() {
+    assert_eq!(Some(256), hexadecimal::hex_to_int("100"));
+}
+
+#[test]
+#[ignore]
+fn test_hex_19ace_is_decimal_105166() {
+    assert_eq!(Some(105166), hexadecimal::hex_to_int("19ace"));
+}
+
+#[test]
+#[ignore]
+fn test_invalid_hex_is_none() {
+    assert_eq!(None, hexadecimal::hex_to_int("carrot"));
+}
+
+#[test]
+#[ignore]
+fn test_black() {
+    assert_eq!(Some(0), hexadecimal::hex_to_int("0000000"));
+}
+
+#[test]
+#[ignore]
+fn test_white() {
+    assert_eq!(Some(16777215), hexadecimal::hex_to_int("ffffff"));
+}
+
+#[test]
+#[ignore]
+fn test_yellow() {
+    assert_eq!(Some(16776960), hexadecimal::hex_to_int("ffff00"));
+}

exercises/nucleotide-codons/.gitignore

@@ -0,0 +1,8 @@
+# Generated by Cargo
+# will have compiled files and executables
+/target/
+**/*.rs.bk
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here http://doc.crates.io/guide.html#cargotoml-vs-cargolock
+Cargo.lock

exercises/nucleotide-codons/Cargo.toml

@@ -0,0 +1,3 @@
+[package]
+name = "nucleotide_codons"
+version = "0.1.0"

exercises/nucleotide-codons/README.md

@@ -0,0 +1,95 @@
+# Nucleotide Codons
+
+Write a function that returns the name of an amino acid a particular codon,
+possibly using shorthand, encodes for.
+
+In DNA sequences of 3 nucleotides, called codons, encode for amino acids. Often
+several codons encode for the same amino acid. The International Union of Pure
+and Applied Chemistry developed a shorthand system for designating groups of
+codons that encode for the same amino acid.
+
+Simply put they've expanded the four letters A, C, G and T with a bunch of
+letters that stand for different possibilities. For example R means A and G.
+So TAR stands for TAA and TAG (think of "TAR" as "TA[AG]" in regex notation).
+
+Write some code that given a codon, which may use shorthand, returns the
+name of the amino acid that that codon encodes for. You will be given
+a list of non-shorthand-codon/name pairs to base your computation on.
+
+See: [wikipedia](https://en.wikipedia.org/wiki/DNA_codon_table).
+
+## Rust Installation
+
+Refer to the [exercism help page][help-page] for Rust installation and learning
+resources.
+
+## Writing the Code
+
+Execute the tests with:
+
+```bash
+$ cargo test
+```
+
+All but the first test have been ignored. After you get the first test to
+pass, open the tests source file which is located in the `tests` directory
+and remove the `#[ignore]` flag from the next test and get the tests to pass
+again. Each separate test is a function with `#[test]` flag above it.
+Continue, until you pass every test.
+
+If you wish to run all tests without editing the tests source file, use:
+
+```bash
+$ cargo test -- --ignored
+```
+
+To run a specific test, for example `some_test`, you can use:
+
+```bash
+$ cargo test some_test
+```
+
+If the specific test is ignored use:
+
+```bash
+$ cargo test some_test -- --ignored
+```
+
+To learn more about Rust tests refer to the [online test documentation][rust-tests]
+
+Make sure to read the [Modules](https://doc.rust-lang.org/book/ch07-02-modules-and-use-to-control-scope-and-privacy.html) chapter if you
+haven't already, it will help you with organizing your files.
+
+## Further improvements
+
+After you have solved the exercise, please consider using the additional utilities, described in the [installation guide](https://exercism.io/tracks/rust/installation), to further refine your final solution.
+
+To format your solution, inside the solution directory use
+
+```bash
+cargo fmt
+```
+
+To see, if your solution contains some common ineffective use cases, inside the solution directory use
+
+```bash
+cargo clippy --all-targets
+```
+
+## Submitting the solution
+
+Generally you should submit all files in which you implemented your solution (`src/lib.rs` in most cases). If you are using any external crates, please consider submitting the `Cargo.toml` file. This will make the review process faster and clearer.
+
+## Feedback, Issues, Pull Requests
+
+The [exercism/rust](https://github.com/exercism/rust) repository on GitHub is the home for all of the Rust exercises. If you have feedback about an exercise, or want to help implement new exercises, head over there and create an issue. Members of the rust track team are happy to help!
+
+If you want to know more about Exercism, take a look at the [contribution guide](https://github.com/exercism/docs/blob/master/contributing-to-language-tracks/README.md).
+
+[help-page]: https://exercism.io/tracks/rust/learning
+[modules]: https://doc.rust-lang.org/book/ch07-02-modules-and-use-to-control-scope-and-privacy.html
+[cargo]: https://doc.rust-lang.org/book/ch14-00-more-about-cargo.html
+[rust-tests]: https://doc.rust-lang.org/book/ch11-02-running-tests.html
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.