Editor Lang Toolkit

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Language support for YAML, TOML and ANSI-coloured text — schema validation, completion, hover, formatting, navigation and terminal colours.

Both language servers are bundled. There is no CLI tool to install, no toolchain to configure, and no telemetry.

Why this extension exists

VS Code ships a complete language service for JSON. For YAML it ships only a TextMate grammar. For TOML it ships nothing at all.

Most extensions that fill these gaps ask you to install a binary first — taplo, buf, a formatter, a linter. That model makes sense for a tool extension. It does not make sense for a language extension: opening a config file should just work.

Features

YAML

Powered by a bundled copy of yaml-language-server.

Validation

• JSON Schema, drafts 04 / 07 / 2019-09 / 2020-12
• Unused anchor detection
• Flow-style rules (yaml.style.flowMapping, yaml.style.flowSequence)
• Mapping key order (yaml.keyOrdering)
• Kubernetes CRD schemas

Schema discovery — four ways, in priority order:

1. A modeline: # yaml-language-server: $schema=<url>
2. An inline $schema property
3. The yaml.schemas setting
4. The SchemaStore catalog, matched automatically by filename

Editing — completion, hover, document symbols, folding, go-to-definition for anchors, rename, document links, selection ranges, code actions, code lenses, formatting and format-on-type.

TOML

Powered by a bundled WebAssembly build of Taplo.

• Syntax highlighting with semantic tokens
• JSON Schema validation, with associations from .taplo.toml or from settings
• Completion, hover, document symbols, folding, rename, document links
• Formatting, configurable through .taplo.toml or the langToolkit.taplo setting

A .taplo.toml in your workspace is picked up automatically — the same file the taplo CLI reads, so editor and CI stay in sync without duplicating configuration.

ANSI

Captured terminal output is rendered with its real colours instead of raw escape codes.

• Full SGR coverage — 16 colours and their bright variants, 256-colour (38;5;n) and true colour (38;2;r;g;b); bold, faint, italic, underline, double underline, strikethrough, overline, inverse and conceal
• Colours follow your theme — mapped to VS Code's terminal.ansi* palette, so there is nothing to configure and nothing to keep in sync with your colour scheme
• Control sequences are recognised, not mangled — cursor moves and line clears are dimmed rather than rendered as garbage. That matters more than it sounds: progress bars, spinners and docker build output are made almost entirely of them
• Preview opens a real editor, not a webview — search, selection, copy and side-by-side scrolling all behave normally, because it is an editor

Colouring applies to the ansi language (.ans, .ansi). To cover other files:

{ "files.associations": { "*.log": "ansi" } }

That trades away the built-in log grammar's timestamp highlighting. It is worth it when the file actually contains escape codes — that grammar renders them as noise anyway.

Requirements

None. Both language servers are bundled.

Commands

All commands are under the Lang Toolkit category in the Command Palette.

Settings

YAML schema associations use the standard yaml.schemas and yaml.schemaStore.* keys, which yaml-language-server reads directly — existing configuration keeps working unchanged.

ANSI colouring has no settings. Colours come from your theme.

Network access

Two things reach the network. Both can be turned off, and neither sends anything about you.

Downloaded grammar content is rejected unless it parses as JSON and declares the source.toml scope, and it is written atomically — a bad response cannot corrupt the bundled grammar.

There is no telemetry.

Size

Bundling two language servers costs space:

Taplo publishes its WebAssembly as base64 inlined into a 34 MB JavaScript file. This extension extracts it into a standalone .wasm at build time, cutting roughly a third off the download — base64's 4/3 expansion is not something gzip can compress back to the density of the raw binary.

Neither server starts until you open a matching file.

Known limitations

• TOML grammar updates need a window reload. contributes.grammars is read when the extension loads, so a newly downloaded grammar cannot take effect in the running window. This is a VS Code mechanism, not something the extension can work around.
• ANSI colouring is tied to the ansi language id. Use files.associations to extend it to other files; there is no regex-based opt-in, because that would require activating the extension on every window start.
• True-colour output creates many decoration types. They are capped at 512 and evicted least-recently-used, so a heavily coloured log will reuse rather than accumulate them.
• YAML formatting is Prettier. The yaml.format.* settings are Prettier options passed through. If you already run Prettier in CI, the two agree by construction.

Credits

This extension stands on three upstream projects, all MIT licensed:

• yaml-language-server — Red Hat
• Taplo — Ferenc Tamás
• vscode-ansi — Ilia Pozdnyakov, whose ANSI parser is used here

Full attributions are in NOTICE.md.

License

MIT — see LICENSE.txt.