From 7906d0c317f69e5ea0b359d020bb33acd43416a5 Mon Sep 17 00:00:00 2001
From: Herwin Weststrate <herwin@snt.utwente.nl>
Date: Thu, 26 Apr 2018 20:26:07 +0200
Subject: [PATCH 1/2] Implemented two-fer exercise

This replaces the old hello-world that is simplified in #69.
---
 exercises/two-fer/README.md        | 10 ++++++++++
 exercises/two-fer/example.scm      |  7 +++++++
 exercises/two-fer/two-fer-test.scm | 25 +++++++++++++++++++++++++
 exercises/two-fer/two-fer.scm      |  2 ++
 4 files changed, 44 insertions(+)
 create mode 100644 exercises/two-fer/README.md
 create mode 100644 exercises/two-fer/example.scm
 create mode 100644 exercises/two-fer/two-fer-test.scm
 create mode 100644 exercises/two-fer/two-fer.scm

diff --git a/exercises/two-fer/README.md b/exercises/two-fer/README.md
new file mode 100644
index 00000000..9b468262
--- /dev/null
+++ b/exercises/two-fer/README.md
@@ -0,0 +1,10 @@
+`Two-fer` or `2-fer` is short for two for one. One for you and one for me.
+
+```text
+"One for X, one for me."
+```
+
+When X is a name or "you".
+
+If the given name is "Alice", the result should be "One for Alice, one for me."
+If no name is given, the result should be "One for you, one for me."
diff --git a/exercises/two-fer/example.scm b/exercises/two-fer/example.scm
new file mode 100644
index 00000000..583b87c9
--- /dev/null
+++ b/exercises/two-fer/example.scm
@@ -0,0 +1,7 @@
+(define-module (two-fer)
+  #:export (two-fer))
+
+(define two-fer
+  (lambda* (#:optional name)
+    (let ((target (or name "you")))
+      (string-concatenate (list "One for " target ", one for me.")))))
diff --git a/exercises/two-fer/two-fer-test.scm b/exercises/two-fer/two-fer-test.scm
new file mode 100644
index 00000000..c815447f
--- /dev/null
+++ b/exercises/two-fer/two-fer-test.scm
@@ -0,0 +1,25 @@
+;; Load SRFI-64 lightweight testing specification
+(use-modules (srfi srfi-64))
+
+;; Suppress log file output. To write logs, comment out the following line:
+(module-define! (resolve-module '(srfi srfi-64)) 'test-log-to-file #f)
+
+;; Require module
+(add-to-load-path (dirname (current-filename)))
+(use-modules (two-fer))
+
+(test-begin "two-fer")
+
+(test-assert "no name given"
+             (equal? (two-fer)
+                     "One for you, one for me."))
+
+(test-assert "a name given"
+             (equal? (two-fer "Alice")
+                     "One for Alice, one for me."))
+
+(test-assert "another name given"
+             (equal? (two-fer "Bob")
+                     "One for Bob, one for me."))
+
+(test-end "two-fer")
diff --git a/exercises/two-fer/two-fer.scm b/exercises/two-fer/two-fer.scm
new file mode 100644
index 00000000..4d2c169a
--- /dev/null
+++ b/exercises/two-fer/two-fer.scm
@@ -0,0 +1,2 @@
+(define-module (two-fer)
+  #:export (two-fer))

From 7385fb07d2ffab200eefc39579a837ad02c35b1a Mon Sep 17 00:00:00 2001
From: Herwin Weststrate <herwin@snt.utwente.nl>
Date: Thu, 10 May 2018 10:26:08 +0200
Subject: [PATCH 2/2] Add two-fer to config.json

---
 config.json | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/config.json b/config.json
index dfd375f2..bf371ed1 100644
--- a/config.json
+++ b/config.json
@@ -120,6 +120,14 @@
       "topics": null,
       "unlocked_by": null,
       "uuid": "9460b65d-dc80-4a95-8782-b395d2cc979e"
+    },
+    {
+      "core": false,
+      "difficulty": 1,
+      "slug": "two-fer",
+      "topics": null,
+      "unlocked_by": null,
+      "uuid": "3ecc2d1c-55e0-45c9-ba35-57d7d8cfd51e"
     }
   ],
   "foregone": [],