Add resistor-color

bin/create-exercise.sh

@@ -22,6 +22,8 @@ while [[ ${pascal} =~ (.*)-(.*) ]]; do
     pascal=${BASH_REMATCH[1]}${BASH_REMATCH[2]^}
 done
 
+snake="${slug//-/_}"
+
 if [[ -z $author ]]; then
     echo
     read -rp "What's your github username? " author
@@ -42,3 +44,5 @@ sed -e "s#hello-world#${slug}#g" exercises/practice/hello-world/hello-world.ipkg
     echo "module ${pascal}"
     echo
 } | tee exercises/practice/${slug}/src/${pascal}.idr > exercises/practice/${slug}/example/${pascal}.idr
+
+touch generators/exercises/${snake}.py

config.json

@@ -216,6 +216,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "resistor-color",
+        "name": "Resistor Color",
+        "uuid": "78e88218-c23e-4210-8721-466768a819cd",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "rotational-cipher",
         "name": "Rotational Cipher",

exercises/practice/resistor-color/.docs/instructions.md

@@ -0,0 +1,39 @@
+# Instructions
+
+If you want to build something using a Raspberry Pi, you'll probably use _resistors_.
+For this exercise, you need to know two things about them:
+
+- Each resistor has a resistance value.
+- Resistors are small - so small in fact that if you printed the resistance value on them, it would be hard to read.
+
+To get around this problem, manufacturers print color-coded bands onto the resistors to denote their resistance values.
+Each band has a position and a numeric value.
+
+The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number.
+
+In this exercise you are going to create a helpful program so that you don't have to remember the values of the bands.
+
+These colors are encoded as follows:
+
+- black: 0
+- brown: 1
+- red: 2
+- orange: 3
+- yellow: 4
+- green: 5
+- blue: 6
+- violet: 7
+- grey: 8
+- white: 9
+
+The goal of this exercise is to create a way:
+
+- to look up the numerical value associated with a particular color band
+- to list the different band colors
+
+Mnemonics map the colors to the numbers, that, when stored as an array, happen to map to their index in the array:
+Better Be Right Or Your Great Big Values Go Wrong.
+
+More information on the color encoding of resistors can be found in the [Electronic color code Wikipedia article][e-color-code].
+
+[e-color-code]: https://en.wikipedia.org/wiki/Electronic_color_code

exercises/practice/resistor-color/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "src/ResistorColor.idr"
+    ],
+    "test": [
+      "test/src/Main.idr"
+    ],
+    "example": [
+      "example/ResistorColor.idr"
+    ]
+  },
+  "blurb": "Convert a resistor band's color to its numeric representation.",
+  "source": "Maud de Vries, Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/issues/1458"
+}

exercises/practice/resistor-color/.meta/tests.toml

@@ -0,0 +1,22 @@
+# 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.
+
+[49eb31c5-10a8-4180-9f7f-fea632ab87ef]
+description = "Color codes -> Black"
+
+[0a4df94b-92da-4579-a907-65040ce0b3fc]
+description = "Color codes -> White"
+
+[5f81608d-f36f-4190-8084-f45116b6f380]
+description = "Color codes -> Orange"
+
+[581d68fa-f968-4be2-9f9d-880f2fb73cf7]
+description = "Colors"

exercises/practice/resistor-color/example/ResistorColor.idr

@@ -0,0 +1,22 @@
+module ResistorColor
+
+import Data.Vect
+
+export
+colors : Vect 10 String
+colors =
+  [ "black"
+  , "brown"
+  , "red"
+  , "orange"
+  , "yellow"
+  , "green"
+  , "blue"
+  , "violet"
+  , "grey"
+  , "white"
+  ]
+
+export
+colorCode : String -> Maybe (Fin 10)
+colorCode color = elemIndex color colors

exercises/practice/resistor-color/pack.toml

@@ -0,0 +1,10 @@
+[custom.all.resistor-color]
+type = "local"
+path = "."
+ipkg = "resistor-color.ipkg"
+test = "test/test.ipkg"
+
+[custom.all.resistor-color-test]
+type = "local"
+path = "test"
+ipkg = "test.ipkg"

exercises/practice/resistor-color/resistor-color.ipkg

@@ -0,0 +1,3 @@
+package resistor-color
+modules = ResistorColor
+sourcedir = "src"

exercises/practice/resistor-color/src/ResistorColor.idr

@@ -0,0 +1,11 @@
+module ResistorColor
+
+import Data.Vect
+
+export
+colorCode : String -> Maybe (Fin 10)
+colorCode color = ?colorCode_rhs
+
+export
+colors : Vect 10 String
+colors = ?colors_rhs

exercises/practice/resistor-color/test/src/Main.idr

@@ -0,0 +1,25 @@
+module Main
+
+import System
+import Tester
+import Tester.Runner
+
+import ResistorColor
+import Data.Vect
+
+tests : List Test
+tests =
+  [ test "Black"  (assertEq (colorCode "black") $ Just 0)
+  , test "White"  (assertEq (colorCode "white") $ Just 9)
+  , test "Orange" (assertEq (colorCode "orange") $ Just 3)
+  , test "Colors" (assertEq colors ["black", "brown", "red", "orange", "yellow", "green", "blue", "violet", "grey", "white"])
+  , test "invalid color" (assertEq (colorCode "teal") $ Nothing)
+  ]
+
+export
+main : IO ()
+main = do
+  success <- runTests tests
+  if success
+     then putStrLn "All tests passed"
+     else exitFailure

exercises/practice/resistor-color/test/test.ipkg

@@ -0,0 +1,6 @@
+package resistor-color-test
+depends = resistor-color
+  , tester
+main = Main
+executable = "resistor-color-test"
+sourcedir = "src"

generators/exercises/resistor_color.py

@@ -0,0 +1,29 @@
+
+EXTRA_CASES = [
+    {
+        "description": "invalid color",
+        "property": "colorCode",
+        "input": { "color": "teal" },
+        "expected": {}
+    }
+]
+
+def header():
+    return "import Data.Vect\n"
+
+def extra_cases():
+    return EXTRA_CASES
+
+def generate_test(case):
+    property = case["property"]
+    expected = case["expected"]
+    if property == "colors":
+        expected = str(expected).replace("'", '"')
+        return f'assertEq {property} {expected}'
+
+    if expected.__class__ == dict:
+        expected = "Nothing"
+    else:
+        expected = f'Just {expected}'
+    color = case["input"]["color"]
+    return f'assertEq ({property} "{color}") $ {expected}'

generators/generate.py

@@ -57,6 +57,9 @@ def write_test_file(f, mod, exercise, cases):
     if hasattr(mod, "header"):
         f.write(mod.header())
     f.write(f"\n")
+    if hasattr(mod, "extra_cases"):
+        cases = cases[:]
+        cases.extend(mod.extra_cases())
     f.write(f"tests : List Test\n")
     f.write(f"tests =\n")
     separator = '['