Add parallel-letter-frequency exercise (#174)

config.json

@@ -18,6 +18,20 @@
   "test_runner": {
     "average_run_time": 2
   },
+  "files": {
+    "solution": [
+      "%{kebab_slug}.wren"
+    ],
+    "test": [
+      "%{kebab_slug}.spec.wren"
+    ],
+    "example": [
+      ".meta/proof.ci.wren"
+    ],
+    "exemplar": [
+      ".meta/exemplar.wren"
+    ]
+  },
   "exercises": {
     "practice": [
       {
@@ -685,6 +699,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 7
+      },
+      {
+        "slug": "parallel-letter-frequency",
+        "name": "Parallel Letter Frequency",
+        "uuid": "9f322f6a-26e7-4595-9a13-36965657bac6",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 7
       }
     ]
   },

exercises/practice/parallel-letter-frequency/.docs/instructions.append.md

@@ -0,0 +1,5 @@
+# ignore
+
+You can read about concurrency in Wren [in the manual][concurrency].
+
+[concurrency]: https://wren.io/concurrency.html

exercises/practice/parallel-letter-frequency/.docs/instructions.md

@@ -0,0 +1,7 @@
+# Instructions
+
+Count the frequency of letters in texts using parallel computation.
+
+Parallelism is about doing things in parallel that can also be done sequentially.
+A common example is counting the frequency of letters.
+Create a function that returns the total frequency of each letter in a list of texts and that employs parallelism.

exercises/practice/parallel-letter-frequency/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "parallel-letter-frequency.wren"
+    ],
+    "test": [
+      "parallel-letter-frequency.spec.wren"
+    ],
+    "example": [
+      ".meta/proof.ci.wren"
+    ]
+  },
+  "blurb": "Count the frequency of letters in texts using parallel computation."
+}

exercises/practice/parallel-letter-frequency/.meta/proof.ci.wren

@@ -0,0 +1,78 @@
+// ------------------------------------------------------------------
+class Frequency {
+  static ofText(text) {
+    return text.codePoints.reduce(Frequency.new()) {|freq, cp|
+      var char
+      if (65 <= cp && cp <= 90) char = String.fromCodePoint(cp + 32)
+      if (97 <= cp && cp <= 122) char = String.fromCodePoint(cp)
+      if (char != null) freq.incr(char)
+      return freq
+    }
+  }
+
+  construct new() {
+    _map = {}
+  }
+
+  keys { _map.keys }
+  [key] { _map[key] }
+  [key]=(value) { _map[key] = value }
+
+  toMap { _map }
+  toString { _map.toString }
+
+  incr(key) { incr(key, 1) }
+  incr(key, amount) { _map[key] = (_map.containsKey(key) ? _map[key] : 0) + amount }
+
+  addAll(other) {
+    if (other is Frequency) {
+      other.keys.each {|key|
+        incr(key, other[key])
+      }
+    }
+  }
+}
+
+// ------------------------------------------------------------------
+class ParallelLetterFrequency {
+  construct new(inputs) {
+    _texts = inputs
+  }
+
+  nonConcurrent() {
+    return _texts.reduce(Frequency.new()) {|freq, text|
+      freq.addAll(Frequency.ofText(text))
+      return freq
+    }.toMap
+  }
+
+  concurrent() {
+    // create a fiber for each input text
+    var fibers = _texts.map {|text|
+      return Fiber.new {|str|
+        Fiber.yield()   // so the first `call` doesn't wait for the result
+        var freq = Frequency.ofText(str)
+        Fiber.yield(freq)
+      }
+    }.toList
+
+    // then send a piece of text to each fiber
+    (0..._texts.count).each {|i|
+      fibers[i].call(_texts[i])
+    }
+
+    // then collect the results
+    var result = Frequency.new()
+    fibers.each {|fiber|
+      var freq = fiber.call()
+      result.addAll(freq)
+    }
+
+    return result.toMap
+  }
+
+  calculateFrequencies() {
+    //return nonConcurrent()
+    return concurrent()
+  }
+}

exercises/practice/parallel-letter-frequency/.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.
+
+[c054d642-c1fa-4234-8007-9339f2337886]
+description = "no texts"
+
+[818031be-49dc-4675-b2f9-c4047f638a2a]
+description = "one text with one letter"
+
+[c0b81d1b-940d-4cea-9f49-8445c69c17ae]
+description = "one text with multiple letters"
+
+[708ff1e0-f14a-43fd-adb5-e76750dcf108]
+description = "two texts with one letter"
+
+[1b5c28bb-4619-4c9d-8db9-a4bb9c3bdca0]
+description = "two texts with multiple letters"
+
+[6366e2b8-b84c-4334-a047-03a00a656d63]
+description = "ignore letter casing"
+
+[92ebcbb0-9181-4421-a784-f6f5aa79f75b]
+description = "ignore whitespace"
+
+[bc5f4203-00ce-4acc-a5fa-f7b865376fd9]
+description = "ignore punctuation"
+
+[68032b8b-346b-4389-a380-e397618f6831]
+description = "ignore numbers"
+
+[aa9f97ac-3961-4af1-88e7-6efed1bfddfd]
+description = "Unicode letters"
+include = false
+comment = "wren doesn't have a lot of string manipulation functionality"
+comment = "it can't lowercase an arbitrary unicode letter"
+
+[7b1da046-701b-41fc-813e-dcfb5ee51813]
+description = "combination of lower- and uppercase letters, punctuation and white space"
+
+[4727f020-df62-4dcf-99b2-a6e58319cb4f]
+description = "large texts"
+
+[adf8e57b-8e54-4483-b6b8-8b32c115884c]
+description = "many small texts"

exercises/practice/parallel-letter-frequency/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2023 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/parallel-letter-frequency/package.wren

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

exercises/practice/parallel-letter-frequency/parallel-letter-frequency.wren

@@ -0,0 +1,9 @@
+class ParallelLetterFrequency {
+  construct new(inputs) {
+    // implement me
+  }
+
+  calculateFrequencies() {
+    // implement me
+  }
+}