add-practice-exercise

#!/usr/bin/env bash

# Synopsis:
# Scaffold the files for a new practice exercise.
# After creating the exercise, follow the instructions in the output.

# Example:
# bin/add-practice-exercise two-fer

# Example with difficulty:
# bin/add-practice-exercise -d 5 two-fer

# Example with author and difficulty:
# bin/add-practice-exercise -a foo -d 3 two-fer

set -euo pipefail
scriptname=$0

help_and_exit() {
    echo >&2 "Scaffold the files for a new practice exercise."
    echo >&2 "Usage: ${scriptname} [-h] [-a author] [-d difficulty] <exercise-slug>"
    echo >&2 "Where: author is the GitHub username of the exercise creator."
    echo >&2 "     : difficulty is between 1 (easiest) to 10 (hardest)."
    exit 1
}

die() { echo >&2 "$*"; exit 1; }

required_tool() {
    command -v "${1}" >/dev/null 2>&1 ||
        die "${1} is required but not installed. Please install it and make sure it's in your PATH."
}

require_files_template() {
    jq -e --arg key "${1}" '.files[$key] | length > 0' config.json > /dev/null ||
        die "The '.files.${1}' array in the 'config.json' file is empty. Please add at least one file. See https://exercism.org/docs/building/tracks/config-json#h-files for more information."
}

required_tool jq
required_tool curl

require_files_template "solution"
require_files_template "test"
require_files_template "example"

[[ -f ./bin/fetch-configlet ]] || die "Run this script from the repo's root directory."

author=''
difficulty='4'
while getopts :ha:d: opt; do
    case $opt in
        h) help_and_exit ;;
        a) author=$OPTARG ;;
        d) difficulty=$OPTARG ;;
        ?) echo >&2 "Unknown option: -$OPTARG"; help_and_exit ;;
    esac
done
shift "$((OPTIND - 1))"

(( $# >= 1 )) || help_and_exit

slug="${1}"
snake_slug=${1//-/_}

if [[ -z "${author}" ]]; then
    read -rp 'Your GitHub username: ' author
fi

./bin/fetch-configlet
./bin/configlet create --practice-exercise "${slug}" --author "${author}" --difficulty "${difficulty}"

filter='.exercises.practice |= sort_by(.difficulty, (.name|ascii_upcase))'
jq "${filter}" config.json > config.sorted && mv config.sorted config.json

exercise_dir="exercises/practice/${slug}"
files=$(
    jq -r --arg dir "${exercise_dir}" --arg q "'" '
        .files
        | to_entries
        | map({key: .key, value: (.value | map($q + $dir + "/" + . + $q) | join(" and "))})
        | from_entries
    ' "${exercise_dir}/.meta/config.json"
)

cp exercises/practice/hello-world/.busted "exercises/practice/${slug}/.busted"

mkdir -p canonical-data
github="https://raw.githubusercontent.com/exercism/problem-specifications/refs/heads/main/exercises/${slug}/canonical-data.json"

curl -s -o "canonical-data/${slug}.json" "$github"


camel_slug=$(perl -pe 's/(?:^|-)([a-z])/\u$1/g' <<< "$slug")
cat << SPEC_GENERATOR > exercises/practice/${slug}/.meta/spec_generator.moon
{
  module_name: '${camel_slug}',
  -- or, module_imports: {'func1', 'func2', ...},

  -- optional:
  test_helpers: [[
  A block of code here, indented 2 spaces
]]

  generate_test: (case, level) ->
    local lines
    -- you may want to "switch case.property" here
    lines = {
      "result = ${camel_slug}.#{case.property} #{case.input}",
      "expected = #{quote case.expected}",
      "assert.are.equal expected, result"
    }
    table.concat [indent line, level for line in *lines], '\n'
}
SPEC_GENERATOR


cat << NEXT_STEPS

Your next steps are:

1.  Create the test suite ==>  $(jq -r '.test' <<< "${files}")

    - A stub test generator awaits you -->  'exercises/practice/${slug}/.meta/spec_generator.moon'
        - If you don't want it, delete it.
        - Otherwise, populate it and run it -->  $ bin/generate-spec ${slug}

    - The tests should be based on the canonical data -->  ./canonical-data/${slug}.json
    - Any test cases you don't implement, mark them in 'exercises/practice/${slug}/.meta/tests.toml' with "include = false"

2.  Create the example solution ==>  $(jq -r '.example' <<< "${files}")

3.  Verify the example solution passes the tests ==>  $ bin/verify-exercises ${slug}

4.  Create the stub solution ==>  $(jq -r '.solution' <<< "${files}")

5.  Update the 'difficulty' value for the exercise's entry in the 'config.json' file in the repo's root

6.  Validate CI using 'bin/configlet lint' and 'bin/configlet fmt'
NEXT_STEPS