From 19f42f400b88dd199685e3bd6960877f29eed407 Mon Sep 17 00:00:00 2001 From: Benjamin Barenblat Date: Thu, 25 Jun 2015 19:50:45 -0400 Subject: Initial commit, including basic editing support --- main.ur | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 main.ur (limited to 'main.ur') diff --git a/main.ur b/main.ur new file mode 100644 index 0000000..6eb1562 --- /dev/null +++ b/main.ur @@ -0,0 +1,97 @@ +(* Copyright 2015 the Massachusetts Institute of Technology + +Licensed under the Apache License, Version 2.0 (the "License"); you may not use +this file except in compliance with the License. You may obtain a copy of the +License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software distributed +under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR +CONDITIONS OF ANY KIND, either express or implied. See the License for the +specific language governing permissions and limitations under the License. *) + +structure Configuration = struct + val main_page_name = "Main Page" + val wiki_title = "UrWiki demo" +end + +type id = int + +table commit : { Id : id, + Created : time, + Content : string } + PRIMARY KEY Id +sequence commit_id_next + +table article : { Title : string, + Head : id } + PRIMARY KEY Title, + CONSTRAINT Head + FOREIGN KEY Head REFERENCES commit(Id) + +fun commit_article title text : transaction unit = + id <- nextval commit_id_next; + creation_time <- now; + dml (INSERT INTO commit (Id, Created, Content) + VALUES ({[id]}, {[creation_time]}, {[text]})); + (* TODO(bbaren): This is ugly. Use CAS instead? *) + sql_error <- tryDml (INSERT INTO article (Title, Head) + VALUES ({[title]}, {[id]})); + case sql_error of + None => + (* We created a new article. *) + return () + | Some _ => + (* The article already exists. *) + dml (UPDATE article + SET Head = {[id]} + WHERE Title = {[title]}) + +fun wiki requested_article_title = + extant_articles <- + queryL (SELECT article.Title, commit.Content + FROM article LEFT JOIN commit ON article.Head = commit.Id + WHERE article.Title = {[requested_article_title]}); + let + val article = + case extant_articles of + Nil => {Title = requested_article_title, Body = "Not found."} + | art :: Nil => {Title = art.Article.Title, + Body = show art.Commit.Content} + | _ :: _ :: _ => error + + Multiple articles with title + ‘{[requested_article_title]}’ + + in + article_body_source <- source article.Body; + return + + + + {[if article.Title = Configuration.main_page_name + then Configuration.wiki_title + else article.Title ^ " – " ^ Configuration.wiki_title]} + + + +

{[Configuration.wiki_title]}

+ + {[text]}} />
+
+