Add matrix exercise (#98)

* Add matrix exercise

* Fix difficulty to 3

config.json

@@ -263,6 +263,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "matrix",
+        "name": "Matrix",
+        "uuid": "c82cc59d-9428-48c8-8c17-908f1dc0ffb3",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "pangram",
         "name": "Pangram",

exercises/practice/matrix/.docs/instructions.md

@@ -0,0 +1,38 @@
+# Instructions
+
+Given a string representing a matrix of numbers, return the rows and columns of that matrix.
+
+So given a string with embedded newlines like:
+
+```text
+9 8 7
+5 3 2
+6 6 7
+```
+
+representing this matrix:
+
+```text
+    1  2  3
+  |---------
+1 | 9  8  7
+2 | 5  3  2
+3 | 6  6  7
+```
+
+your code should be able to spit out:
+
+- A list of the rows, reading each row left-to-right while moving top-to-bottom across the rows,
+- A list of the columns, reading each column top-to-bottom while moving from left-to-right.
+
+The rows for our example matrix:
+
+- 9, 8, 7
+- 5, 3, 2
+- 6, 6, 7
+
+And its columns:
+
+- 9, 5, 6
+- 8, 3, 6
+- 7, 2, 7

exercises/practice/matrix/.meta/Example.roc

@@ -0,0 +1,34 @@
+module [row, column]
+
+parseRow : Str -> Result (List I64) [InvalidNumStr]
+parseRow = \rowStr ->
+    rowStr
+    |> Str.trim
+    |> Str.split " "
+    |> List.map Str.trim
+    |> List.dropIf Str.isEmpty
+    |> List.mapTry Str.toI64
+
+parseMatrix : Str -> Result (List (List I64)) [InvalidNumStr]
+parseMatrix = \matrixStr ->
+    matrixStr
+    |> Str.trim
+    |> Str.split "\n"
+    |> List.mapTry parseRow
+
+column : Str, U64 -> Result (List I64) [InvalidNumStr, OutOfBounds]
+column = \matrixStr, index ->
+    if index == 0 then
+        Err OutOfBounds
+    else
+        matrix = parseMatrix? matrixStr
+        matrix |> List.mapTry \r -> r |> List.get (index - 1)
+
+row : Str, U64 -> Result (List I64) [InvalidNumStr, OutOfBounds]
+row = \matrixStr, index ->
+    if index == 0 then
+        Err OutOfBounds
+    else
+        matrix = parseMatrix? matrixStr
+        result = matrix |> List.get? (index - 1)
+        Ok result

exercises/practice/matrix/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "ageron"
+  ],
+  "files": {
+    "solution": [
+      "Matrix.roc"
+    ],
+    "test": [
+      "matrix-test.roc"
+    ],
+    "example": [
+      ".meta/Example.roc"
+    ]
+  },
+  "blurb": "Given a string representing a matrix of numbers, return the rows and columns of that matrix.",
+  "source": "Exercise by the JumpstartLab team for students at The Turing School of Software and Design.",
+  "source_url": "https://turing.edu"
+}

exercises/practice/matrix/.meta/template.j2

@@ -0,0 +1,14 @@
+{%- import "generator_macros.j2" as macros with context -%}
+{{ macros.canonical_ref() }}
+{{ macros.header() }}
+
+import {{ exercise | to_pascal }} exposing [row, column]
+
+{% for case in cases -%}
+# {{ case["description"] }}
+expect
+    matrixStr = {{ case["input"]["string"] | to_roc_multiline_string | indent(8) }}
+    result = matrixStr |> {{ case["property"] | to_camel }} {{ case["input"]["index"] | to_roc }}
+    result == Ok {{ case["expected"] | to_roc }}
+
+{% endfor %}

exercises/practice/matrix/.meta/tests.toml

@@ -0,0 +1,34 @@
+# 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.
+
+[ca733dab-9d85-4065-9ef6-a880a951dafd]
+description = "extract row from one number matrix"
+
+[5c93ec93-80e1-4268-9fc2-63bc7d23385c]
+description = "can extract row"
+
+[2f1aad89-ad0f-4bd2-9919-99a8bff0305a]
+description = "extract row where numbers have different widths"
+
+[68f7f6ba-57e2-4e87-82d0-ad09889b5204]
+description = "can extract row from non-square matrix with no corresponding column"
+
+[e8c74391-c93b-4aed-8bfe-f3c9beb89ebb]
+description = "extract column from one number matrix"
+
+[7136bdbd-b3dc-48c4-a10c-8230976d3727]
+description = "can extract column"
+
+[ad64f8d7-bba6-4182-8adf-0c14de3d0eca]
+description = "can extract column from non-square matrix with no corresponding row"
+
+[9eddfa5c-8474-440e-ae0a-f018c2a0dd89]
+description = "extract column where numbers have different widths"

exercises/practice/matrix/Matrix.roc

@@ -0,0 +1,9 @@
+module [row, column]
+
+column : Str, U64 -> Result (List I64) _
+column = \matrixStr, index ->
+    crash "Please implement the 'column' function"
+
+row : Str, U64 -> Result (List I64) _
+row = \matrixStr, index ->
+    crash "Please implement the 'row' function"

exercises/practice/matrix/matrix-test.roc

@@ -0,0 +1,89 @@
+# These tests are auto-generated with test data from:
+# https://github.com/exercism/problem-specifications/tree/main/exercises/matrix/canonical-data.json
+# File last updated on 2024-09-20
+app [main] {
+    pf: platform "https://github.com/roc-lang/basic-cli/releases/download/0.15.0/SlwdbJ-3GR7uBWQo6zlmYWNYOxnvo8r6YABXD-45UOw.tar.br",
+}
+
+main =
+    Task.ok {}
+
+import Matrix exposing [row, column]
+
+# extract row from one number matrix
+expect
+    matrixStr = "1"
+    result = matrixStr |> row 1
+    result == Ok [1]
+
+# can extract row
+expect
+    matrixStr =
+        """
+        1 2
+        3 4
+        """
+    result = matrixStr |> row 2
+    result == Ok [3, 4]
+
+# extract row where numbers have different widths
+expect
+    matrixStr =
+        """
+        1 2
+        10 20
+        """
+    result = matrixStr |> row 2
+    result == Ok [10, 20]
+
+# can extract row from non-square matrix with no corresponding column
+expect
+    matrixStr =
+        """
+        1 2 3
+        4 5 6
+        7 8 9
+        8 7 6
+        """
+    result = matrixStr |> row 4
+    result == Ok [8, 7, 6]
+
+# extract column from one number matrix
+expect
+    matrixStr = "1"
+    result = matrixStr |> column 1
+    result == Ok [1]
+
+# can extract column
+expect
+    matrixStr =
+        """
+        1 2 3
+        4 5 6
+        7 8 9
+        """
+    result = matrixStr |> column 3
+    result == Ok [3, 6, 9]
+
+# can extract column from non-square matrix with no corresponding row
+expect
+    matrixStr =
+        """
+        1 2 3 4
+        5 6 7 8
+        9 8 7 6
+        """
+    result = matrixStr |> column 4
+    result == Ok [4, 8, 6]
+
+# extract column where numbers have different widths
+expect
+    matrixStr =
+        """
+        89 1903 3
+        18 3 1
+        9 4 800
+        """
+    result = matrixStr |> column 2
+    result == Ok [1903, 3, 4]
+