add rna transcription (#40)

* exercise boilerplate

* example solution

* format test

Author: TheRealOwenRees

config.json

@@ -149,6 +149,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "rna-transcription",
+        "name": "RNA Transcription",
+        "uuid": "ae2cde1b-f9e7-4473-88f8-484c3f4349f8",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "rotational-cipher",
         "name": "Rotational Cipher",

exercises/practice/rna-transcription/.docs/instructions.md

@@ -0,0 +1,20 @@
+# Instructions
+
+Your task is to determine the RNA complement of a given DNA sequence.
+
+Both DNA and RNA strands are a sequence of nucleotides.
+
+The four nucleotides found in DNA are adenine (**A**), cytosine (**C**), guanine (**G**), and thymine (**T**).
+
+The four nucleotides found in RNA are adenine (**A**), cytosine (**C**), guanine (**G**), and uracil (**U**).
+
+Given a DNA strand, its transcribed RNA strand is formed by replacing each nucleotide with its complement:
+
+- `G` -> `C`
+- `C` -> `G`
+- `T` -> `A`
+- `A` -> `U`
+
+~~~~exercism/note
+If you want to look at how the inputs and outputs are structured, take a look at the examples in the test suite.
+~~~~

exercises/practice/rna-transcription/.docs/introduction.md

@@ -0,0 +1,16 @@
+# Introduction
+
+You work for a bioengineering company that specializes in developing therapeutic solutions.
+
+Your team has just been given a new project to develop a targeted therapy for a rare type of cancer.
+
+~~~~exercism/note
+It's all very complicated, but the basic idea is that sometimes people's bodies produce too much of a given protein.
+That can cause all sorts of havoc.
+
+But if you can create a very specific molecule (called a micro-RNA), it can prevent the protein from being produced.
+
+This technique is called [RNA Interference][rnai].
+
+[rnai]: https://admin.acceleratingscience.com/ask-a-scientist/what-is-rnai/
+~~~~

exercises/practice/rna-transcription/.gitignore

@@ -0,0 +1,2 @@
+node_modules
+**/*.res.js

exercises/practice/rna-transcription/.meta/RnaTranscription.res

@@ -0,0 +1,26 @@
+type dna =
+  | A
+  | C
+  | G
+  | T
+
+let fromString = s => {
+  switch s {
+  | "A" => A
+  | "C" => C
+  | "G" => G
+  | "T" => T
+  | _ => panic("Invalid DNA base")
+  }
+}
+
+let convert = s => {
+  switch s {
+  | A => "U"
+  | C => "G"
+  | G => "C"
+  | T => "A"
+  }
+}
+
+let toRna = dna => dna->String.split("")->Array.map(fromString)->Array.map(convert)->Array.join("")

exercises/practice/rna-transcription/.meta/RnaTranscription.resi

@@ -0,0 +1 @@
+let toRna: string => string

exercises/practice/rna-transcription/.meta/config.json

@@ -0,0 +1,21 @@
+{
+  "authors": [
+    "therealowenrees"
+  ],
+  "files": {
+    "solution": [
+      "src/RnaTranscription.res",
+      "src/RnaTranscription.resi"
+    ],
+    "test": [
+      "tests/RnaTranscription_test.res"
+    ],
+    "example": [
+      ".meta/RnaTranscription.res",
+      ".meta/RnaTranscription.resi"
+    ]
+  },
+  "blurb": "Given a DNA strand, return its RNA complement.",
+  "source": "Hyperphysics",
+  "source_url": "https://web.archive.org/web/20220408112140/http://hyperphysics.phy-astr.gsu.edu/hbase/Organic/transcription.html"
+}

exercises/practice/rna-transcription/.meta/tests.toml

@@ -0,0 +1,28 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[b4631f82-c98c-4a2f-90b3-c5c2b6c6f661]
+description = "Empty RNA sequence"
+
+[a9558a3c-318c-4240-9256-5d5ed47005a6]
+description = "RNA complement of cytosine is guanine"
+
+[6eedbb5c-12cb-4c8b-9f51-f8320b4dc2e7]
+description = "RNA complement of guanine is cytosine"
+
+[870bd3ec-8487-471d-8d9a-a25046488d3e]
+description = "RNA complement of thymine is adenine"
+
+[aade8964-02e1-4073-872f-42d3ffd74c5f]
+description = "RNA complement of adenine is uracil"
+
+[79ed2757-f018-4f47-a1d7-34a559392dbf]
+description = "RNA complement"

exercises/practice/rna-transcription/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Exercism
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.