LSP Features

LSP methods spice-lsp implements today, plus a short note on planned work.

Capability matrix

Full specification of reference hover and net diagnostics: Dialect reference and net semantics.

Server capabilities

{
  "capabilities": {
    "textDocumentSync": {
      "openClose": true,
      "change": 2,
      "save": false
    },
    "documentSymbolProvider": true,
    "definitionProvider": true,
    "referencesProvider": true,
    "hoverProvider": true,
    "documentFormattingProvider": true,
    "documentRangeFormattingProvider": true
  },
  "serverInfo": { "name": "spice-lsp", "version": "0.1.0" }
}

change: 2 is Incremental sync — the client sends edit ranges, not the full buffer every keystroke.

Diagnostics arrive via server-initiated textDocument/publishDiagnostics.

Syntax diagnostics

Symbols and navigation

Document symbols for outline / breadcrumbs:

Navigation: go to definition and find references for subcircuits, models, and parameters. textDocument/references honors context.includeDeclaration (omit definition sites when the client passes false).

Include / library resolution: .include / .inc and HSPICE .lib 'file' entry are followed so model and subcircuit definitions in those files participate in unknown-model checks and go-to-definition. On a .lib 'file' entry (or .include path) line, go to definition on the path opens that file; on the entry name it jumps to the matching .lib entry section header. See Include and library resolution.

Large-file / extracted analysis

In extracted mode (forced, or auto when the buffer reaches the threshold):

• Index keeps .subckt / .model / .param definitions
• Instance symbols and outline children are omitted
• spice/duplicate-name is not emitted
• Unknown-model still reports unique missing model/subckt names (sparse refs)
• Go to definition on an instance’s model/subckt token still works via line classification

Design detail: Large-file / extracted mode.

Semantic diagnostics

Diagnostics from didChange are debounced (~150 ms) so rapid typing does not re-analyze on every keystroke. didOpen publishes immediately. Navigation handlers refresh the in-memory index on demand.

Dialect selection

spiceLsp.dialect is hspice | ngspice | ltspice (default hspice). The VS Code command SPICE LSP: Set Dialect… and a status-bar item change it. The same dialect selects the reference corpus for hover and (later) completion docs.

Design: Multi-dialect support.

Hover

textDocument/hover resolves in order:

1. Curated entry from reference/ for the active dialect (_shared fallback)
2. File-local detail for .subckt / .model / .param symbols
3. No hover

When the cursor is on a directive, option, element keyword, or documented expression form, the server loads the matching entry and returns markdown (summary, syntax, parameter table, examples). You maintain this corpus over time; the LSP indexes and renders it. Authoring guide: Dialect reference and net semantics.

Formatting

textDocument/formatting and textDocument/rangeFormatting return a full-document TextEdit when the buffer would change. Range formatting uses the same full-document pass so instance alignment groups stay consistent. LSP tabSize maps to continuation indentWidth; output always uses spaces.

Rules, CLI (spice-lsp format), and options: Formatter.

Planned

Completion

Element letters, directive names, in-scope model and subcircuit names, snippet templates for .tran / .subckt. Documentation can attach the same reference entries used for hover.

Connectivity diagnostics

Published alongside other diagnostics in publishDiagnostics. Configurable via spiceLsp.diagnostics.* settings.

Client configuration

Testing

Integration coverage includes:

1. initialize returns expected capabilities
2. Open invalid document → diagnostics notification
3. Edit → updated diagnostics (debounced)
4. documentSymbol returns hierarchical outline for .subckt blocks
5. definition on subcircuit reference jumps to .subckt definition
6. definition on .lib 'file' entry path opens the library file; on the entry name jumps to .lib entry
7. references on subcircuit definition lists definition + usages; includeDeclaration: false omits the definition
8. Semantic fixtures (duplicate-instance.cir, unknown-subckt.cir) produce warning codes
9. Hover snapshots match reference entries for the active dialect

Planned: semantic fixtures for dangling / floating warnings once connectivity lands.

See Demo and testing.