add strain

config.json

@@ -74,6 +74,14 @@
         "prerequisites": [],
         "difficulty": 1
       },
+      {
+        "slug": "strain",
+        "name": "Strain",
+        "uuid": "af541ed6-4112-4b61-99dd-fd29424ae859",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
+      },
       {
         "slug": "high-scores",
         "name": "High Scores",

exercises/practice/strain/.docs/instructions.append.md

@@ -0,0 +1,10 @@
+# Instructions append
+
+## Implementaton Notes
+
+The test suite passes a Function class instance to the `keep` and `discard` methods as a [block argument][block-argument].
+To successfully pass the tests, you'll need to call that function inside your code.
+If you're unfamiliar with how to do this, please consult the [Function class documentation][function-class].
+
+[block-argument]: https://wren.io/functions.html#block-arguments
+[function-class]: https://wren.io/modules/core/fn.html

exercises/practice/strain/.docs/instructions.md

@@ -0,0 +1,29 @@
+# Instructions
+
+Implement the `keep` and `discard` operation on collections.
+Given a collection and a predicate on the collection's elements, `keep` returns a new collection containing those elements where the predicate is true, while `discard` returns a new collection containing those elements where the predicate is false.
+
+For example, given the collection of numbers:
+
+- 1, 2, 3, 4, 5
+
+And the predicate:
+
+- is the number even?
+
+Then your keep operation should produce:
+
+- 2, 4
+
+While your discard operation should produce:
+
+- 1, 3, 5
+
+Note that the union of keep and discard is all the elements.
+
+The functions may be called `keep` and `discard`, or they may need different names in order to not clash with existing functions or concepts in your language.
+
+## Restrictions
+
+Keep your hands off that filter/reject/whatchamacallit functionality provided by your standard library!
+Solve this one yourself using other basic tools instead.

exercises/practice/strain/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "strain.wren"
+    ],
+    "test": [
+      "strain.spec.wren"
+    ],
+    "example": [
+      ".meta/proof.ci.wren"
+    ]
+  },
+  "blurb": "Implement the `keep` and `discard` operation on collections.",
+  "source": "Conversation with James Edward Gray II",
+  "source_url": "http://graysoftinc.com/"
+}

exercises/practice/strain/.meta/proof.ci.wren

@@ -0,0 +1,16 @@
+class Strain {
+  static keep(list, predicate) {
+    var kept = []
+    for (item in list) {
+      if (predicate.call(item)) {
+        kept.add(item)
+      }
+    }
+    return kept
+  }
+
+  static discard(list, predicate) {
+    return keep(list) { |x| !predicate.call(x) }
+  }
+}
+

exercises/practice/strain/.meta/tests.toml

@@ -0,0 +1,52 @@
+# 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.
+
+[26af8c32-ba6a-4eb3-aa0a-ebd8f136e003]
+description = "keep on empty list returns empty list"
+
+[f535cb4d-e99b-472a-bd52-9fa0ffccf454]
+description = "keeps everything"
+
+[950b8e8e-f628-42a8-85e2-9b30f09cde38]
+description = "keeps nothing"
+
+[92694259-6e76-470c-af87-156bdf75018a]
+description = "keeps first and last"
+
+[938f7867-bfc7-449e-a21b-7b00cbb56994]
+description = "keeps neither first nor last"
+
+[8908e351-4437-4d2b-a0f7-770811e48816]
+description = "keeps strings"
+
+[2728036b-102a-4f1e-a3ef-eac6160d876a]
+description = "keeps lists"
+
+[ef16beb9-8d84-451a-996a-14e80607fce6]
+description = "discard on empty list returns empty list"
+
+[2f42f9bc-8e06-4afe-a222-051b5d8cd12a]
+description = "discards everything"
+
+[ca990fdd-08c2-4f95-aa50-e0f5e1d6802b]
+description = "discards nothing"
+
+[71595dae-d283-48ca-a52b-45fa96819d2f]
+description = "discards first and last"
+
+[ae141f79-f86d-4567-b407-919eaca0f3dd]
+description = "discards neither first nor last"
+
+[daf25b36-a59f-4f29-bcfe-302eb4e43609]
+description = "discards strings"
+
+[a38d03f9-95ad-4459-80d1-48e937e4acaf]
+description = "discards lists"

exercises/practice/strain/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022 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.

exercises/practice/strain/package.wren

@@ -0,0 +1,14 @@
+import "wren-package" for WrenPackage, Dependency
+import "os" for Process
+
+class Package is WrenPackage {
+  construct new() {}
+  name { "exercism/strain" }
+  dependencies {
+    return [
+      Dependency.new("wren-testie", "0.3.0", "https://github.com/joshgoebel/wren-testie.git")
+    ]
+  }
+}
+
+Package.new().default()

exercises/practice/strain/strain.spec.wren

@@ -0,0 +1,112 @@
+import "wren-testie/testie" for Testie, Expect
+import "./strain" for Strain
+
+Testie.test("Strain") { |do, skip|
+  do.describe("keep") {
+    do.test("keep on empty list returns empty list") {
+      var actual = Strain.keep([]) { |x| true }
+      Expect.value(actual).toEqual([])
+    }
+
+    skip.test("keeps everything") {
+      var actual = Strain.keep([1, 3, 5]) { |x| true }
+      Expect.value(actual).toEqual([1, 3, 5])
+    }
+
+    skip.test("keeps nothing") {
+      var actual = Strain.keep([1, 3, 5]) { |x| false }
+      Expect.value(actual).toEqual([])
+    }
+
+    skip.test("keeps first and last") {
+      var actual = Strain.keep([1, 2, 3]) { |x| x % 2 == 1 }
+      Expect.value(actual).toEqual([1, 3])
+    }
+
+    skip.test("keeps neither first nor last") {
+      var actual = Strain.keep([1, 2, 3]) { |x| x % 2 == 0 }
+      Expect.value(actual).toEqual([2])
+    }
+
+    skip.test("keeps strings") {
+      var list = ["apple", "zebra", "banana", "zombies", "cherimoya", "zealot"]
+      var actual = Strain.keep(list) { |x| x.startsWith("z") }
+      var expected = ["zebra", "zombies", "zealot"]
+      Expect.value(actual).toEqual(expected)
+    }
+
+    skip.test("keeps lists") {
+      var list = [
+        [1, 2, 3],
+        [5, 5, 5],
+        [5, 1, 2],
+        [2, 1, 2],
+        [1, 5, 2],
+        [2, 2, 1],
+        [1, 2, 5]
+      ]
+      var actual = Strain.keep(list) { |x| x.contains(5) }
+      var expected = [
+        [5, 5, 5],
+        [5, 1, 2],
+        [1, 5, 2],
+        [1, 2, 5]
+      ]
+      Expect.value(actual).toEqual(expected)
+    }
+  }
+
+  do.describe("discard") {
+    skip.test("discard on empty list returns empty list") {
+      var actual = Strain.discard([]) { |x| true }
+      Expect.value(actual).toEqual([])
+    }
+
+    skip.test("discards everything") {
+      var actual = Strain.discard([1, 3, 5]) { |x| true }
+      Expect.value(actual).toEqual([])
+    }
+
+    skip.test("discards nothing") {
+      var actual = Strain.discard([1, 3, 5]) { |x| false }
+      Expect.value(actual).toEqual([1, 3, 5])
+    }
+
+    skip.test("discards first and last") {
+      var actual = Strain.discard([1, 2, 3]) { |x| x % 2 == 1 }
+      Expect.value(actual).toEqual([2])
+    }
+
+    skip.test("discards neither first nor last") {
+      var actual = Strain.discard([1, 2, 3]) { |x| x % 2 == 0 }
+      Expect.value(actual).toEqual([1, 3])
+    }
+
+    skip.test("discards strings") {
+      var list = ["apple", "zebra", "banana", "zombies", "cherimoya", "zealot"]
+      var actual = Strain.discard(list) { |x| x.startsWith("z") }
+      var expected = ["apple", "banana", "cherimoya"]
+      Expect.value(actual).toEqual(expected)
+    }
+
+    skip.test("discards lists") {
+      var list = [
+        [1, 2, 3],
+        [5, 5, 5],
+        [5, 1, 2],
+        [2, 1, 2],
+        [1, 5, 2],
+        [2, 2, 1],
+        [1, 2, 5]
+      ]
+      var actual = Strain.discard(list) { |x| x.contains(5) }
+      var expected = [
+        [1, 2, 3],
+        [2, 1, 2],
+        [2, 2, 1]
+      ]
+      Expect.value(actual).toEqual(expected)
+    }
+  }
+}
+

exercises/practice/strain/strain.wren

@@ -0,0 +1,9 @@
+class Strain {
+  static keep(list, predicate) {
+    Fiber.abort("Remove this statement and implement this function")
+  }
+
+  static discard(list, predicate) {
+    Fiber.abort("Remove this statement and implement this function")
+  }
+}