Categorize Git Commits

ChangelogBuilder.re

module Git = {
  type commitish = Sha(string);

  type commit = {
    title: string,
    descriptiong: string,
    author: string,
    date: Date.t
  };

  let getCommitsForRange: (commitish, commitish) => list(commit);
};

module Category = {
  type t =  
    | Feature
    | Bugfix
    | Performance
    | Design
    | Docs;
};

module Rule = {
  type pattern =
    | TitleStartsWith(string)
    | TitleEndsWith(string)
    | TitleContains(string);

  type t =
    | Pattern(pattern)
    | And(list(t))
    | Or(list(t));

  let evaluate: (string, t) => bool;
};

module CategoryRule = {
  type t = {
    category: Category.t,
    rule: Rule.t,
  };

  let make = (category, rule) => {category, rule};
  let bugfix = make(Category.Bugfix);
  let perf = make(Category.Performance);

  let evaulate = (txt, {category, rule}) =>
    Rule.evaluate(txt, rule) ? Some(category) : None;
};

module Changelog = {
  type t = Map.t(Category.t, list(Git.commit));
  let fromCommits: ((Git.commit => option(Category.t)), list(Git.commit)) => t;
};

let categorize = (rules, commit) =>
  List.foldLeft(
    (category, rule) =>
      switch (category) {
      | Some(cat) => Some(cat)
      | None => CategoryRule.evaluate(commit, rule)
      }
    None,
    rules,
  );


/*******************************************************************************
 * Example usage
 ******************************************************************************/

let bugRule = Rule.(or([
  pattern(startsWith(":bug:")),
  pattern(cotains("fixes #"))
]);

let perfRule = Rule.(pattern(startsWith(":rocket:")));

let myRules = [bugRule, perfRule];

Git.(getCommitsForRange(sha("abcdef"), sha("012345")))
  |> Changelog.fromCommits(categorize(myRules));