Add pangram exercise (exercism#322)

Author: BNAndras

config.json

@@ -387,6 +387,14 @@
         "prerequisites": [],
         "difficulty": 1
       },
+      {
+        "slug": "pangram",
+        "name": "Pangram",
+        "uuid": "af3484cd-a74a-4a55-a641-5483d25ca006",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "pop-count",
         "name": "Eliud's Eggs",

exercises/practice/pangram/.docs/instructions.md

@@ -0,0 +1,8 @@
+# Instructions
+
+Your task is to figure out if a sentence is a pangram.
+
+A pangram is a sentence using every letter of the alphabet at least once.
+It is case insensitive, so it doesn't matter if a letter is lower-case (e.g. `k`) or upper-case (e.g. `K`).
+
+For this exercise, a sentence is a pangram if it contains each of the 26 letters in the English alphabet.

exercises/practice/pangram/.docs/introduction.md

@@ -0,0 +1,16 @@
+# Introduction
+
+You work for a company that sells fonts through their website.
+They'd like to show a different sentence each time someone views a font on their website.
+To give a comprehensive sense of the font, the random sentences should use **all** the letters in the English alphabet.
+
+They're running a competition to get suggestions for sentences that they can use.
+You're in charge of checking the submissions to see if they are valid.
+
+~~~~exercism/note
+Pangram comes from Greek, παν γράμμα, pan gramma, which means "every letter".
+
+The best known English pangram is:
+
+> The quick brown fox jumps over the lazy dog.
+~~~~

exercises/practice/pangram/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "pangram.rkt"
+    ],
+    "test": [
+      "pangram-test.rkt"
+    ],
+    "example": [
+      ".meta/example.rkt"
+    ]
+  },
+  "blurb": "Determine if a sentence is a pangram.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Pangram"
+}

exercises/practice/pangram/.meta/example.rkt

@@ -0,0 +1,12 @@
+#lang racket
+
+(provide pangram?)
+
+(define alphabet-length
+ (length (string->list "abcdefghijklmnopqrstuvwxyz")))
+
+(define (pangram? sentence)
+ (define letters (for/set ([chr sentence]
+                           #:when (char-alphabetic? chr))
+                  (char-downcase chr)))
+ (eq? (set-count letters) alphabet-length))

exercises/practice/pangram/.meta/tests.toml

@@ -0,0 +1,45 @@
+# 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.
+
+[64f61791-508e-4f5c-83ab-05de042b0149]
+description = "empty sentence"
+
+[74858f80-4a4d-478b-8a5e-c6477e4e4e84]
+description = "perfect lower case"
+
+[61288860-35ca-4abe-ba08-f5df76ecbdcd]
+description = "only lower case"
+
+[6564267d-8ac5-4d29-baf2-e7d2e304a743]
+description = "missing the letter 'x'"
+
+[c79af1be-d715-4cdb-a5f2-b2fa3e7e0de0]
+description = "missing the letter 'h'"
+
+[d835ec38-bc8f-48e4-9e36-eb232427b1df]
+description = "with underscores"
+
+[8cc1e080-a178-4494-b4b3-06982c9be2a8]
+description = "with numbers"
+
+[bed96b1c-ff95-45b8-9731-fdbdcb6ede9a]
+description = "missing letters replaced by numbers"
+
+[938bd5d8-ade5-40e2-a2d9-55a338a01030]
+description = "mixed case and punctuation"
+
+[2577bf54-83c8-402d-a64b-a2c0f7bb213a]
+description = "case insensitive"
+include = false
+
+[7138e389-83e4-4c6e-8413-1e40a0076951]
+description = "a-m and A-M are 26 different characters but not a pangram"
+reimplements = "2577bf54-83c8-402d-a64b-a2c0f7bb213a"

exercises/practice/pangram/pangram-test.rkt

@@ -0,0 +1,42 @@
+#lang racket/base
+
+(require "pangram.rkt")
+
+(module+ test
+  (require rackunit rackunit/text-ui)
+
+  (define suite
+    (test-suite
+     "pangram tests"
+
+     (test-false "empty sentence"
+                 (pangram? ""))
+
+     (test-true "perfect lower case"
+                (pangram? "abcdefghijklmnopqrstuvwxyz"))
+
+     (test-true "only lower case"
+                (pangram? "the quick brown fox jumps over the lazy dog"))
+
+     (test-false "missing the letter 'x'"
+                 (pangram? "a quick movement of the enemy will jeopardize five gunboats"))
+
+     (test-false "missing the letter 'h'"
+                 (pangram? "five boxing wizards jump quickly at it"))
+
+     (test-true "with underscores"
+                (pangram? "the_quick_brown_fox_jumps_over_the_lazy_dog"))
+
+     (test-true "with numbers"
+                (pangram? "the 1 quick brown fox jumps over the 2 lazy dogs"))
+
+     (test-false "missing letters replaced by numbers"
+                 (pangram? "t7h3 qu1ck brown fox jumps ov3r 7h3 lazy dog"))
+
+     (test-true "mixed case and punctuation"
+                (pangram? "\"Five quacking Zephyrs jolt my wax bed.\""))
+
+     (test-false "a-m and A-M are 26 different characters but not a pangram"
+                 (pangram? "abcdefghijklm ABCDEFGHIJKLM"))))
+
+  (run-tests suite))

exercises/practice/pangram/pangram.rkt

@@ -0,0 +1,6 @@
+#lang racket
+
+(provide pangram?)
+
+(define (pangram? sentence)
+  (error "Not implemented yet"))