Level0L for Visual Studio Code

Editor support for Level0L, the text format used by the Level0 OpenStreetMap editor.

Features

• Syntax highlighting for entity headers (node, way, relation, changeset), IDs and versions, coordinates, tags, way nodes and relation members, comments. Negative (new) IDs, the delete prefix - and the conflict marker ! get their own scopes so themes can make them stand out. Object versions are drawn at reduced opacity, in the theme's own color, since they are metadata rather than something to edit. A conflict written by Level0 is shown like a git merge conflict: the comment block holding your edits gets the theme's "current" background, the ! entity with the server version the "incoming" background. Lines the Level0 parser would reject are marked as invalid.
• Clickable links (Ctrl/Cmd+click):
  • object IDs in entity headers and in nd / wy / rel members open the object on openstreetmap.org; the version number after the dot opens that exact version (way 123.4 links 4 to /way/123/history/4), useful when the server has moved on since the download;
  • node coordinates open the map at that location;
  • values that point somewhere open the target: Wikidata items (wikidata, brand:wikidata, name:etymology:wikidata, any *:wikidata), Wikipedia articles (wikipedia = lang:Title, *:wikipedia, the old wikipedia:lang form), Commons files and categories (wikimedia_commons, image = File:*), websites (website, url, image, contact:website, source:url, bare domains included), phone numbers as tel: links (phone, mobile, fax, contact:phone, phone:*), e-mail as mailto:, Mapillary and Panoramax picture ids, and social accounts under contact:* (Facebook, Instagram, Twitter/X, YouTube, TikTok, Telegram, WhatsApp, Viber, LinkedIn, VK, Mastodon, Matrix, Bluesky and others) given either as a URL or a bare user name. Values separated by ; get one link each;
  • tag keys and simple enumerated values open their wiki page. The target is resolved on click through taginfo: the page in your language when it exists, the English page otherwise, and the taginfo key or tag page when there is no wiki page at all, so a click never lands on a missing page. Without taginfo (setting off, offline) the link goes to the English wiki page.
• Hovers backed by taginfo: hover a tag key or value to see its wiki description in your language, approval status (obsolete and deprecated tags are flagged), usage counts by object type, top values for a key, what object types the tag applies to and commonly combined tags. Keys and tags taginfo has never seen are flagged as possible typos. Responses are cached for a day; tags inside the changeset block are ignored.
• Navigation between objects of one file. Go to Definition (F12, Cmd/Ctrl+click) on nd 123, wy 456 or rel 789 jumps to the header of that node, way or relation when it is in the document; Peek Definition (Alt+F12) shows it inline. Find All References (Shift+F12) on an id, in a header or a member line, lists every way and relation that uses it. Members whose object is in the document have no web link, so Cmd/Ctrl+click goes to the local definition; members of objects not in the document open osm.org.
• Completion. At the start of a line: snippets for node, way, relation and changeset. On an indented line: tag keys, first those already used in the file, then the most used keys from taginfo matching what you typed; picking one inserts key = and opens the value list. After =: the key's most used values from taginfo with their share, count and wiki description in your language, narrowed to values containing what you typed once there are two characters; free-text keys such as name and identifier keys such as wikidata get no list. After nd, wy or rel: ids of the matching objects in the file with their summary. After a member id in a relation: roles used with that relation's type, most used first, limited to the member's object type. In the changeset block: the standard changeset keys with a short explanation.
• Outline and folding. The outline view, breadcrumbs, sticky scroll and Go to Symbol (Cmd/Ctrl+Shift+O) list every object with a one-line summary (amenity=cafe · Kyiv Coffee, type=multipolygon · landuse=grass), its tags and members as children, deleted objects struck through. Each object folds as a block, as does every run of comment lines.
• Diagnostics. The validation rules of the Level0 parser are ported one to one: conflicts, deleting unsaved objects, nodes without coordinates, ways with fewer than two nodes, relations without members, members on the wrong entity type, duplicated tags, unparsable lines. Errors are the ones Level0 refuses to upload; warnings are reported but uploaded. Taginfo adds warnings for keys unused in OSM, values unused with their key, and keys or tags the wiki marks deprecated or obsolete. Values are checked only when they look like an enumerated value and the key is enumerated (a few thousand distinct values at most, like amenity, not millions like name). Checks run 700 ms after the last edit; one request per distinct key and per distinct unusual tag, cached for a day, at most four in flight.
• JOSM interoperability. Text copied with the JOSM comfort0 plugin carries a #comment after every header and member line. Members with such comments are read correctly, and the command "Level0L: Strip member comments (JOSM comfort0)" removes them, which is needed before pasting into Level0 itself: its parser takes a comment after a relation member as part of the role, so those lines are marked with an information diagnostic.
• Line comments with #.

Files are recognized by the .l0l and .level0 extensions, or by a first line that starts with an entity header.

Installation

From the VS Code Marketplace or Open VSX, search for "Level0L". To install a downloaded .vsix instead: Extensions view, the "..." menu, "Install from VSIX...", or code --install-extension level0l-0.1.0.vsix.

Settings

Taginfo requests go out with a level0-vscode/<version> User-Agent as its usage policy asks. Failures are logged to the "Level0L" output channel and never block the editor.

Development

npm install
npm test

npm test compiles and runs the unit tests of the parser, links, completion and outline modules with Node's built-in test runner; they need no VS Code and no network. Then press F5 in VS Code to launch an Extension Development Host with the samples/ folder opened.

To build a .vsix: npx @vscode/vsce package. Releases are published with npx @vscode/vsce publish (Marketplace) and npx ovsx publish (Open VSX).

License

MIT