added full Language server for URDF and xacro by pichifkes · Pull Request #9 · OTL/vscode-urdf

pichifkes · 2026-05-21T14:04:16Z

Read the readme and try it out.
its nice

error messages, dropdowns for variables, the whole shtick
This one is limited to Linux ONLY

- Full Gazebo property schema: mu1/mu2/kp/kd/selfCollide etc. with type validation (float, bool, int) inside <gazebo> blocks - gazebo reference= validated against known links/joints - Completions for reference= (links+joints) and element names inside <gazebo> - Fix ${-var} and ${pi/2} falsely flagged as undefined xacro properties - Eliminate double XML parse per keystroke (check_schema now reuses parsed doc) - Deduplicate byte_range_to_lsp (pub(crate) in document.rs) - Extract is_xacro_element() and resolve_effective() helpers - HashSet for duplicate detection, remove unused imports and allow suppressor Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Three new checks in check(): - Isolated link (no joints at all): Error/Warning - Multiple roots (>1 link with no parent joint but with children): Error/Warning - Cycle: reports the joint that closes the loop, always Error Severity is WARNING for xacro files (tree may be completed by included files) and ERROR for plain URDF. Includes 4 unit tests covering isolated, multiple-roots, cycle, and valid chain. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

roxmltree reports XML parse errors at the position where the inconsistency was first detected — typically the closing tag. For a misspelled opening tag like <mateaaaarial> ... </material>, this meant the error appeared on the (correct) closing tag, hiding the actual typo. Add a small fallback tag-balance scanner in document::parse that runs only when roxmltree fails. It tracks opening/closing tag balance and reports: - Mismatched tag: opened <A> but closed with </B> — on the opening tag - Closing tag </X> has no matching opening tag — on the closing tag - Tag <X> is never closed — on the opening tag Honours quoted attribute values, self-closing tags, comments, CDATA, DOCTYPE, and processing instructions. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

New module xacro_eval.rs implements a small recursive-descent expression evaluator: +, -, *, /, %, unary -, parentheses, the pi constant, math functions (sin/cos/tan/abs/sqrt/radians/degrees), and variable references with recursive resolution and cycle detection. features::inlay_hints scans the requested range for ${...} substitutions, evaluates each via xacro_eval, and emits an inlay hint right after the closing '}' showing the computed value. document::XacroProperty now also stores the raw value attribute so the evaluator can resolve variable references without re-parsing the XML. Includes 9 unit tests (8 for the evaluator, 1 end-to-end exercising the inlay_hints function on a realistic URDF snippet). Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

The server was advertising CompletionOptions::default() with no trigger characters, so VS Code only invoked completion when the user typed identifier characters. Typing \${ or \" never popped up the dropdown. Also fix an edge case in the xacro regex_match: when the prefix is exactly \${ at column 0 (no closing brace anywhere), open > close evaluated 0 > 0 = false, suppressing the completion. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

The xacro property scanner looked for the next '}' anywhere in the file. When a ${... was left unclosed (e.g. radius=\"\${asaso\"), the scanner happily consumed text past the closing quote and across element boundaries until it found a stray '}'. The resulting \"varname\" contained spaces/operators, so the existing operator-character guard silently dropped it — no diagnostic at all. Fix: while scanning for the closing brace, abort at attribute/element boundaries ('\"', \"'\", '<', newline). On abort emit an \"Unclosed xacro expression: missing '}'\" error on the ${... span. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

VS Code defaults editor.quickSuggestions.strings to \"off\", which suppresses completion when typing identifier characters inside a \"...\" attribute value. Since virtually every useful URDF/xacro completion (link names, joint names, xacro property names) appears inside attribute strings, the default made the dropdown essentially invisible — only the registered trigger characters ($, {, \", <) fired it. Override the default for files with the urdf language id via contributes.configurationDefaults. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

For each diagnostic whose message we recognise, offer a quick-fix: - Undefined link / joint / mimic / gazebo reference → typo-correction candidates from the appropriate symbol pool (Levenshtein distance, up to 3 suggestions within edit distance ~len/3) - Undefined xacro property → typo correction wrapped in \${...} - Element missing required attribute → insert attr=\"\" right after the element name Wires up the LSP code_action capability and handler. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

When roxmltree::Document::parse failed (e.g. a single malformed line), document::parse returned an empty Document while check() and check_schema() still ran. With empty xacro_properties, every \${var} reference in the file was wrongly flagged as 'Undefined xacro property' — drowning the real XML-parse error in cascade noise. Add a parse_ok flag on Document; main::validate now runs the semantic checks only when parse_ok is true. The XML-parse-error diagnostic still reaches the user, so they can fix that first. Regression test added. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Every multi-line element (link, joint, visual, collision, inertial, gazebo, plugin, material with children, xacro:macro, etc.) becomes a collapsible region. The closing tag stays visible when collapsed. Walks the parsed roxmltree::Document; emits one FoldingRange per element where the closing tag is at least two lines below the opening. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

roxmltree 0.20 emits errors like \"expected '=' not 'e' at 26:19\" — the position lives at the END of the message after \" at \". Our old parser only matched a leading \"ROW:COL message\" prefix, failed silently, and fell back to (0, 0), which is why a typo on line 26 was reported at the top of the file. parse_xml_error_pos now first tries the tail-of-message form, then falls back to the leading form for compatibility. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

LSP color provider: - document_color handler walks the XML for <color rgba=\"r g b a\"/> and returns a ColorInformation per match so VS Code can render an inline clickable swatch - color_presentation returns the space-separated literal that replaces the rgba value when the user picks a new colour - Wired through the LSP capabilities TextMate grammar additions: - New scopes: urdf-structure (parent/child/mimic), urdf-material (material/color/texture), urdf-inertial (mass/inertia) - New gazebo-properties scope for mu1/mu2/kp/kd/etc. — distinct color - New urdf-attributes scope so common attribute names (name=, link=, joint=, type=, rgba=, xyz=, rpy=, size=, radius=, length=, etc.) highlight as attribute names document::attr_value_range was made pub(crate) so features.rs can reuse it for the color range. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Previous scopes (entity.name.tag.material.urdf, entity.name.tag.inertial.urdf, entity.name.tag.structure.urdf) fell back to entity.name.tag in most themes — i.e. exactly the same color as a plain XML tag, so the new groupings produced no visible differentiation. Switched to scopes that themes commonly style distinctly: - parent/child/mimic → variable.parameter - material/color/texture → support.class - mass/inertia → support.function Other scopes already used well-themed roots (keyword.control, storage.type, support.type, support.constant, entity.other.attribute-name). Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

The previous grammar inherited text.xml and tried to override scopes with top-level patterns using \`(?<=</?)(name)(?=...)\` lookbehind. The problem: text.xml's tag pattern uses begin=\"(</?)([\\w:.-]+)\" which consumes the entire \`<name\` as one match before any of our top-level patterns get tried at the position of the name. So our overrides never ran — every URDF/xacro file looked identical to plain XML. Replace the grammar with our own \`tag\` begin/end repository entry that captures the tag name via a nested patterns array, dispatching to specific scope rules: - robot/link/joint/transmission/gazebo → keyword.control - visual/collision/inertial/geometry/origin/axis/limit/dynamics/etc → storage.type - box/cylinder/sphere/mesh → support.type - material/color/texture → support.class - mass/inertia → support.function - parent/child/mimic → variable.parameter - mu1/mu2/kp/kd/etc. → support.constant - xacro:* → entity.name.function Also handles attribute names (entity.other.attribute-name), joint type values inside strings (constant.language), \${...} interpolation, XML prolog, and comments. Falls back to text.xml for anything we don't specifically know about. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

In TextMate's vscode-textmate engine, ^ and $ are line anchors — even when re-scanning a captured value. The capture is still part of the original line, so ^material never matches because the line starts with whitespace, not 'material'. As a result every URDF tag fell through to the .+ fallback, scoped as entity.name.tag.xml — exactly what the scope inspector confirmed. Switch to \A/\z (start/end of string, Oniguruma absolute anchors) which anchor to the start/end of the captured substring itself. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…ures The previous design captured the tag name and used a nested patterns array to dispatch to specific scopes. Whether due to anchor handling or capture-pattern semantics in vscode-textmate, none of the specific patterns matched — every tag ended up with the .+ fallback scope (entity.name.tag.xml), as confirmed by the scope inspector showing joint, link, material all at the same color. Replace the single dispatching tag rule with one begin/end rule per category. The scope is assigned directly in beginCaptures[2] — no nested patterns, no anchor tricks, just a literal alternation in the begin regex that matches only the tag names for that category. Order in the top-level patterns list ensures the specific rules win before the generic-tag fallback. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Copilot

Pull request overview

This PR upgrades the extension from primarily snippets/highlighting into a full URDF/xacro language extension by introducing a Rust-based LSP server (stdio) plus a thin TypeScript VS Code client, and wiring it into the extension manifest and build pipeline (Linux-only per README).

Changes:

Added a Rust language server (urdf-lsp) implementing diagnostics, completions, hover/definition/references/rename, inlay hints, code actions, folding, and color features.
Registered a dedicated urdf language id with a custom TextMate grammar + language configuration for URDF/xacro editing.
Updated packaging/build workflow, docs, examples, and VS Code dev tasks/launch config.

Reviewed changes

Copilot reviewed 19 out of 23 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
syntaxes/urdf.tmLanguage.json	Adds a TextMate grammar for URDF/xacro highlighting.
language-configuration.json	Adds comment/bracket/autoclosing configuration for the `urdf` language.
package.json	Registers `urdf` language + grammar + snippets; points extension entry to `client/out`.
README.md	Documents new LSP-based feature set and build/run instructions.
CHANGELOG.md	Notes the 0.4.0-dev LSP rewrite and Linux-only status.
examples/sample.urdf	Adds a sample URDF for manual testing/demonstration.
client/src/extension.ts	Implements the VS Code client that spawns the Rust server over stdio.
client/tsconfig.json	Adds strict TS build config for the client.
client/package.json	Declares client dependency on `vscode-languageclient`.
client/package-lock.json	Locks client dependencies.
server/src/main.rs	Implements the LSP server entrypoint and registers capabilities/handlers.
server/src/document.rs	Adds XML parsing + symbol extraction + tag-balance fallback diagnostics helpers.
server/src/diagnostics.rs	Adds semantic + schema-like validation diagnostics and related tests.
server/src/features.rs	Adds IDE features (completion/hover/definition/rename/etc.) and quick-fix actions.
server/src/xacro_eval.rs	Adds `${...}` expression evaluation + formatting and unit tests.
server/Cargo.toml	Declares the Rust server crate and dependencies.
server/Cargo.lock	Locks Rust dependencies for the server.
.vscodeignore	Updates packaging exclusions for client/server build artifacts.
.vscode/tasks.json	Replaces watch tasking with explicit build tasks for server/client.
.vscode/launch.json	Updates extension host launch config to use the new build task and output path.
.gitignore	Updates ignored build outputs for the new client/server layout.
.github/workflows/build.yml	Adds CI build + vsix packaging workflow (Linux).

Files not reviewed (1)

client/package-lock.json: Language not supported

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pichifkes · 2026-05-21T22:38:26Z

+          npm install -g @vscode/vsce
+          vsce package --no-dependencies --out urdf-$(node -p "require('./package.json').version")-linux-x64.vsix


Added esbuild to client/package.json — extension.ts gets bundled into a single out/extension.js with --bundle --external:vscode, which inlines vscode-languageclient and its deps into that one file. The .vsix ships only the bundle, so client/node_modules being excluded no longer matters.

pichifkes · 2026-05-21T22:28:33Z

+client/out/**/*.map
+client/src/**
+client/tsconfig.json
+client/node_modules/**


Bundled the client with esbuild — client/package.json now has a bundle script (esbuild ... --bundle --platform=node --external:vscode) that produces a self-contained client/out/extension.js, so vscode-languageclient/node is inlined and .vscodeignore excluding client/node_modules/ is fine.

pichifkes · 2026-05-21T22:20:35Z

+    // Walk backwards through all occurrences of the attribute name.
+    let mut search = prefix;
+    loop {
+        let Some(pos) = search.find(attr) else {
+            return false;
+        };
+        let after_attr = &search[pos + attr.len()..];
+        // Skip optional whitespace
+        let after_ws = after_attr.trim_start_matches(|c: char| c == ' ' || c == '\t');
+        if let Some(rest) = after_ws.strip_prefix('=') {
+            let after_eq = rest.trim_start_matches(|c: char| c == ' ' || c == '\t');
+            if let Some(after_quote) = after_eq.strip_prefix('"') {
+                // We are inside the quote only if there is no closing `"` after it.
+                if !after_quote.contains('"') {
+                    return true;
+                }
+            }
+        }


Left-boundary check (features.rs:496-497) — the byte before the match must
be whitespace, <, or /. That rejects xlink, parent_link, _link, etc.

Right-boundary check (features.rs:499-508) — after the matched name there
must be optional whitespace, =, optional whitespace, ", and no closing " yet
(cursor still inside the value).

Loop, not single-shot — if the first hit fails boundary checks, it keeps
scanning further into the prefix instead of giving up.

And there are explicit tests at features.rs:846-858 covering the exact cases
from the review: xlink=, parent_link=, and the "already-closed quote" case
(cursor past the value).

pichifkes · 2026-05-21T22:22:00Z

+/// True when the cursor byte offset falls inside an open `<gazebo …>` block.
+fn inside_gazebo_block(text: &str, offset: usize) -> bool {
+    let before = &text[..offset.min(text.len())];
+    let last_open  = before.rfind("<gazebo");
+    let last_close = before.rfind("</gazebo");
+    match (last_open, last_close) {
+        (Some(open), Some(close)) => open > close,
+        (Some(_), None)           => true,
+        _                         => false,


Fixed. Self-closing <gazebo …/> now returns false via scan_to_tag_close (the
canonical quote-aware scanner), with test coverage at features.rs:868
(inside_gazebo_block_after_self_closing) and features.rs:880 (quoted />
doesn't false-trigger).

pichifkes · 2026-05-21T22:26:12Z

+/// Parse a row:col prefix from roxmltree error messages (e.g. "9:5 unexpected close tag").
+/// Returns 0-indexed (line, character). Falls back to (0, 0) if the format doesn't match.
+/// Walk the document tracking opening/closing tag balance. Returns a single
+/// diagnostic positioned on the actual misspelled (or unclosed) opening tag,
+/// rather than at the closing tag where the inconsistency was detected.
+/// Used as a fallback when roxmltree::Document::parse fails.


Fixed. The doc comment on scan_tag_balance (lines 261–264) now only describes the tag-balance scanner. no leftover row/col parsing language. parse_xml_error_pos has its own separate comment at line 414.

pichifkes · 2026-05-21T22:24:16Z

+        "gazebo-prop-tag": {
+            "begin": "(</?)(mu1|mu2|mu|kp|kd|maxVel|minDepth|maxContacts|selfCollide|turnGravityOff|gravity|implicitSpringDamper|dampingFactor|laserRetro|stopCfm|stopErp|fudgeFactor)(?=[\\s/>])",
+            "beginCaptures": {
+                "1": { "name": "punctuation.definition.tag.xml" },
+                "2": { "name": "support.constant.gazebo" }
+            },


Fixed. Added material, sensor, plugin to the regex, plus a doc comment pointing to GAZEBO_PROPS in diagnostics.rs as the single source of truth.

…building.

….vsix

… interconnected scripts

pichifkes · 2026-05-25T08:40:29Z

hey @OTL , I validated the code.

pichifkes · 2026-05-27T10:16:21Z

@OTL are you there?

pichifkes · 2026-05-28T10:03:12Z

Mr. @OTL I'm here waiting desperately for you to tell me what is wrong with my code

OTL · 2026-05-28T11:50:25Z

Hello. I'm very busy, so please wait patiently. /************************* Takashi Ogura (小倉崇) ***@***.*** *************************/ 2026年5月28日(木) 19:03 pichifkes ***@***.***>:

…

*pichifkes* left a comment (OTL/vscode-urdf#9) <#9 (comment)> Mr. @OTL <https://github.com/OTL> I'm here waiting desperately for you to tell me what is wrong with my code — Reply to this email directly, view it on GitHub <#9?email_source=notifications&email_token=AABSSJRBIPISXFG6PIAYAXD45AFHPA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINJWGI4TAMBUG432M4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLDGN5XXIZLSL5RWY2LDNM#issuecomment-4562900477>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABSSJRHU7L32O5MW27TGUD45AFHPAVCNFSM6AAAAACZHXRNAKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DKNRSHEYDANBXG4> . You are receiving this because you were mentioned.Message ID: ***@***.***>

pichifkes and others added 22 commits May 21, 2026 09:49

Created URDF diagnostic rules

7b9d89a

fix syntax

22c1972

Fix a lot of problems

a53b1ae

mathematical operations excluded from variable names

46f5bab

add ReadMe

50f5609

added vsix file

43da97f

OTL requested a review from Copilot May 21, 2026 14:08

Copilot started reviewing on behalf of OTL May 21, 2026 14:09 View session

Copilot AI reviewed May 21, 2026

View reviewed changes

pichifkes closed this May 21, 2026

pichifkes reopened this May 21, 2026

pichifkes added 2 commits May 22, 2026 01:02

address brutal CoPilot review: SSOT tables, UTF8 encoding, establish …

a364983

…building.

stop tracking prebuilt (.vsix). rewrite install instructions.

657750d

pichifkes marked this pull request as draft May 22, 2026 08:02

pichifkes added 6 commits May 22, 2026 11:55

prep 0.5.0 marketplace release

4fd04a4

release.yml: use darwin-universal to avoid macos-13 queue

2a015d1

release.yml: split universal binary into darwin-x64 and darwin-arm64 …

9e98a09

….vsix

fix skipping variables for complex operations

0abd7bc

Change version name; same fix as before with a 0.1 added

9a0ce14

added cross file variable checks

5fcca32

pichifkes marked this pull request as ready for review May 22, 2026 18:18

pichifkes marked this pull request as draft May 22, 2026 18:20

Added cross file links

e4e93b2

pichifkes marked this pull request as ready for review May 24, 2026 07:26

pichifkes added 2 commits May 24, 2026 10:33

chnage the code to look at the files like a giant urdf inted of small…

da89946

… interconnected scripts

fix 'Joint not connected' bug; fix 'is xacro=flase' bug

ff7bd47

pichifkes closed this May 27, 2026

pichifkes reopened this May 27, 2026

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added full Language server for URDF and xacro #9

added full Language server for URDF and xacro #9
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		npm install -g @vscode/vsce
		vsce package --no-dependencies --out urdf-$(node -p "require('./package.json').version")-linux-x64.vsix

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