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fsouza's solution

to Pangram in the OCaml Track

Published at Jul 06 2019 · 1 comment
Instructions
Test suite
Solution

Note:

This exercise has changed since this solution was written.

Determine if a sentence is a pangram. A pangram (Greek: παν γράμμα, pan gramma, "every letter") is a sentence using every letter of the alphabet at least once. The best known English pangram is:

The quick brown fox jumps over the lazy dog.

The alphabet used consists of ASCII letters a to z, inclusive, and is case insensitive. Input will not contain non-ASCII symbols.

Getting Started

  1. Install the Exercism CLI.

  2. Install OCaml.

  3. For library documentation, follow Useful OCaml resources.

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make

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Source

Wikipedia https://en.wikipedia.org/wiki/Pangram

test.ml

open OUnit2
open Pangram

let ae exp got _test_ctxt = assert_equal ~printer:string_of_bool exp got

let tests = [
   "sentence empty" >::
      ae false (is_pangram "");
   "recognizes a perfect lower case pangram" >::
      ae true (is_pangram "abcdefghijklmnopqrstuvwxyz");
   "pangram with only lower case" >::
      ae true (is_pangram "the quick brown fox jumps over the lazy dog");
   "missing character 'x'" >::
      ae false (is_pangram "a quick movement of the enemy will jeopardize five gunboats");
   "another missing character, e.g. 'h'" >::
      ae false (is_pangram "five boxing wizards jump quickly at it");
   "pangram with underscores" >::
      ae true (is_pangram "the_quick_brown_fox_jumps_over_the_lazy_dog");
   "pangram with numbers" >::
      ae true (is_pangram "the 1 quick brown fox jumps over the 2 lazy dogs");
   "missing letters replaced by numbers" >::
      ae false (is_pangram "7h3 qu1ck brown fox jumps ov3r 7h3 lazy dog");
   "pangram with mixed case and punctuation" >::
      ae true (is_pangram "\"Five quacking Zephyrs jolt my wax bed.\"");
   "upper and lower case versions of the same character should not be counted separately" >::
      ae false (is_pangram "the quick brown fox jumps over with lazy FX");
]

let () =
  run_test_tt_main ("pangram tests" >::: tests)

pangram.ml

open Base

let init_set =
  Set.of_list (module Char)
  @@ List.init
       ~f:(fun i ->
         let a = Char.to_int 'a' in
         i + a |> Char.of_int_exn)
       26

let is_pangram phrase =
  phrase
  |> String.fold ~init:init_set ~f:(fun acc ch -> ch |> Char.lowercase |> Set.remove acc)
  |> Set.is_empty

pangram.mli

val is_pangram : string -> bool

Community comments

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Avatar of barisere

Wow. How did you think up this? Kudos.

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