SPICE support for VSCode

SPICE syntax highlighting reference leoheck/sublime-spice TextMate rules.

Other useful rules reference see: 1995parham/vim-spice

Snippets reference: bzisjo/vscode-spice-support

Maintained by Xuan Li, Wiener Technology, Beijing.

GitHub repos

lxTHU/vscode-spice

See also

Seeing SPICE in VSCode Marketplace

Requires VS Code 1.67.0 or newer.

Docs

• CHANGELOG.md — release history
• docs/SYNTAX.md — SPICE/HSPICE vs Spectre dialect comparison & navigation matrix
• docs/ARCHITECTURE.md — navigation engine design (.lib dual syntax, .param/section scope, Spectre support)
• docs/RELEASE.md — build, package, and publish guide
• docs/ROADMAP.md — demand evidence and versioned roadmap
• docs/TODO.md — known limitations and backlog

Features

Code Folding

Folding is supported for the following block structures:

• .subckt / .ends
• .lib / .endl — only the section definition form .lib NAME … .endl NAME starts a fold; the file reference form .lib 'file' NAME does not start a fold block.
• .control / .endc
• .if / .endif
• .data / .enddata
• .model blocks (parameter list opened by ( and closed by ))
• .statistics / .endstatistics
• .section / .endsection
• Spectre: subckt / ends, if / endif, statistics, process, section / endsection

.param / .options are single statements (parameters may use + continuation) and are not treated as fold blocks.

Folding Shortcuts

These are all VS Code default shortcuts (no configuration needed) and work well for process-library files that contain many .lib / .model blocks:

Recommended workflow for browsing a process library: press Ctrl+K Ctrl+1 to collapse every top-level .lib section to a single line so you can survey all corners at a glance; expand the corner you need, then use Ctrl+Shift+[ to drill down layer by layer.

To view or customize all folding shortcuts: open the Command Palette (Ctrl+Shift+P) and type fold.

Syntax Highlighting

SPICE Standard

• Comments: *, //, ;, $
• Hierarchical Blocks: .subckt/.ends, .lib/.endl, .control/.endc, .if/.endif
• Simulation Commands: .ac, .dc, .tran, .op, .noise, .tf, .disto, .four
• Configuration Commands: .include, .model, .param, .global, .options, .temp, .step, .func
• Measurement Commands: .meas/.measure
• Output Commands: .save, .print, .plot, .probe
• Circuit Elements:
  • Passive: R (Resistor), C (Capacitor), L (Inductor), K (Coupling)
  • Active: D (Diode), Q (BJT), J (JFET), M (MOSFET), Z (MESFET)
  • Sources: V (Voltage), I (Current), B (Behavioral), E (VCVS), F (CCCS), G (VCCS), H (CCVS)
  • Other: T (Transmission Line), S/W (Switch), X (Subcircuit Instance)
• Functions: Math functions (abs, sin, cos, log, etc.) and source functions (pulse, pwl, sin, exp)
• Numbers:
  • Scientific notation (e.g., 1.5e+09, 2.3E-12) — the exponent is colored distinctly
  • Engineering notation (e.g., 1k, 100n, 2.2u) — the scale suffix is colored distinctly
• Operators: Comparison and logical operators
• Keywords: Sweep parameters (SWEEP, START, STOP, STEP), analysis types (dec, oct, lin)

Spectre (Cadence)

• Keywords: parameters, simulator, analysis, design, model, instance, global, include, info, save, plot, print, assert, alter, statistics, process, section, connect, options, temp, lib, if/else/endif, end
• Analysis Types: ac, dc, tran, noise, stb, pss, pac, pnoise, xf, dcmatch, acmatch, sens
• Devices: resistor, capacitor, inductor, diode, bipolar, mosfet, jfet, vsource, isource, vcvs, vccs, ccvs, cccs, tline, switch
• Blocks: subckt/ends, if/endif, statistics, process, section/endsection

Code Snippets

SPICE Structure

• .sub - Subcircuit definition
• .lib - Library declaration
• .con - Control block
• .if / .ifelse / .elseif - Conditional statements
• .inc - Include file
• .mod - Model definition
• .glob - Global node
• .opt - Options
• .temp - Temperature
• .func - Function definition
• .data - Data block
• .end - End of netlist

SPICE Analysis Commands

• .ac - AC analysis (basic, sweep, data-driven)
• .dc - DC analysis (basic, sweep, data-driven)
• .tran - Transient analysis (basic, with start, sweep, data-driven)
• .op - Operating point
• .noise - Noise analysis
• .tf - Transfer function
• .four - Fourier analysis
• .disto - Distortion analysis
• .step - Parameter sweep
• .node - Nodeset

SPICE Measurement Commands

• .meas - Measure rise/fall/delay
• .measwhen - Measure when condition
• .measfind - Measure find at value
• .measavg - Measure average
• .measrms - Measure RMS
• .measpp - Measure peak-to-peak
• .measmin - Measure minimum
• .measmax - Measure maximum

SPICE Output Commands

• .save - Save signal
• .print - Print output
• .plot - Plot output
• .probe - Probe output

SPICE Circuit Elements

• R - Resistor
• C - Capacitor
• L - Inductor
• D - Diode
• Q - BJT Transistor
• M - MOSFET
• J - JFET
• X - Subcircuit instance
• Vdc / Vac - Voltage source (DC/AC)
• Idc - Current source DC
• Vpulse / Vsin - Pulse/Sinusoidal voltage source
• T - Transmission line
• S - Switch
• E / F / G / H - Controlled sources

SPICE Source Functions

• pulse - Pulse waveform
• sin - Sinusoidal waveform
• exp - Exponential waveform
• pwl - Piece-wise linear
• sffm - Single FM
• am - AM modulated

SPICE Templates

• tranfull - Complete transient analysis template
• acfull - Complete AC analysis template
• dcfull - Complete DC analysis template

Spectre Commands

• subckt - Subcircuit definition
• parameters - Parameter definition
• simulator - Simulator language
• include - Include file
• global - Global node
• save - Save signal
• options - Simulation options
• info - Information
• design - Design specification
• model - Model definition
• assert - Assertion
• statistics - Statistics block
• process - Process block
• section / endsection - Section block
• if / ifelse / endif - Conditional statements
• end - End of netlist

Spectre Analysis

• ac - AC analysis
• dc - DC analysis
• tran - Transient analysis
• noise - Noise analysis
• stb - Stability analysis
• pss - Periodic steady state
• pac - Periodic AC
• pnoise - Periodic noise

Spectre Devices

• resistor - Resistor
• capacitor - Capacitor
• inductor - Inductor
• diode - Diode
• mosfet - MOSFET
• bipolar - BJT
• jfet - JFET
• vsource - Voltage source
• isource - Current source
• vcvs / vccs / ccvs / cccs - Controlled sources
• tline - Transmission line
• switch - Switch

Language Features

• Comment Toggle: Use Ctrl+/ to toggle comments
• Bracket Matching: Automatic bracket matching for .subckt/.ends, .lib/.endl, etc.
• Auto Closing: Automatic closing of brackets, parentheses, and quotes
• Indentation: Smart indentation for hierarchical blocks
• Code Folding: Fold/unfold block structures

Netlist Navigation

IDE-style navigation across HSPICE and Spectre netlists, including process libraries (PDKs) linked via .INCLUDE / .INC / .LIB (HSPICE) or include / section (Spectre). The navigation engine runs entirely in-process — no language-server dependency. See docs/SYNTAX.md for what each dialect supports.

Navigation works in both dialects in any .sp / .scs / .lib file. The examples below use HSPICE dot-command syntax; the Spectre equivalents (bare subckt/model/parameters/include/section) work the same way.

Scope-local net connectivity (0.4.0)

Place the cursor on a node name to inspect its electrical endpoints inside the current lexical scope: either the current file's top level or one .SUBCKT / subckt body.

• Matching endpoints are highlighted with VS Code's native Document Highlight.
• Shift+F12 opens native Peek References for the scoped net. A subcircuit header port counts as the declaration endpoint.
• Hover shows the original net spelling, lexical scope, endpoint count, and the current mapping such as X1.A or M1.drain.
• Unambiguous subcircuit calls show clickable formalPort: Inlay Hints. Missing or ambiguous definitions, model targets, and port-count mismatches produce no hint.
• F12 on an X actual node still jumps to the positional formal port. Primitive device nodes do not gain an invented definition.

Hints use the standard VS Code setting and are on by default. To disable them only for SPICE files:

"[spice]": {
  "editor.inlayHints.enabled": "off"
}

Connectivity is deliberately lexical in 0.4.0. Same-name nets in another subcircuit or file are not merged; 0, .global, and Spectre global names remain local to each lexical scope. Workspace-wide and hierarchical connectivity are later, demand-gated capabilities.

Net lookup is intentionally case-insensitive in both dialects and preserves the spelling at each endpoint. Spectre simulators may distinguish names by case, so case-only-distinct Spectre nets are a documented 0.4.0 navigation limit rather than a claim about simulator connectivity.

Go to Definition (F12)

• From an X instance name → its .SUBCKT definition.
• From a M / Q / D / J / S / Z device model name → its .MODEL definition.
• From a node on an X instance → the matching port in the .SUBCKT header.
• From a variable reference inside an expression (e.g. dL in lmin = 'L0-(dL+dmis)') → its .param definition.
• From a section name in .lib 'file' section → the corresponding .LIB section … .ENDL definition.
• Works across files via .INCLUDE / .INC / .LIB chains — included files do not need to be open.

When the same name is defined in multiple places (e.g. a model/param defined in several .LIB section corners), VS Code's native Peek picker lists all definitions to choose from.

Hover (Ctrl+K Ctrl+I)

• Over a subcircuit name → its port list.
• Over a model name → its type (e.g. nmos, pnp).
• Over a net endpoint → its lexical scope, endpoint count, and current X-port or primitive-terminal mapping.
• Over a .param variable → its value(s) (all definitions when multiple corners exist).
• Over an environment variable ($VAR / ${VAR}) inside an .INCLUDE path → its resolved value.

Find All References (Shift+F12)

• All X instances referencing a subcircuit, or all device instances referencing a model.
• All expression sites referencing a .param variable (inside other params and model cards).
• On a net token, all endpoints with the same case-insensitive name in the current lexical scope.

Outline

The Outline panel lists every .SUBCKT, .MODEL, and .param, nested under their containing .LIB section, with click-to-navigate.

.INCLUDE / .LIB file links

File paths in .INCLUDE / .INC and .lib 'file' section statements are Ctrl+Click links that open the target file; environment variables in paths are resolved.

.LIB section scope (corner selection)

HSPICE .lib 'file' section selects which definitions inside file are active. The extension resolves the active scope automatically when possible, and lets you pin it manually otherwise:

• Automatic (determined scope) — if the current file is included by an upstream netlist via .lib 'thisFile' section, that section is used; F12 jumps straight to the in-scope definition with no ambiguity.
• Manual (ambiguous scope) — when a file is opened directly (e.g. a shared PDK that many top-level netlists could include), run SPICE: Select Active .LIB Section from the Command Palette or editor context menu to pin a section for the session; SPICE: Clear Manual Section Scope resets it. When no scope is pinned and the scope is ambiguous, F12 returns all definitions so you can pick.

Scope resolution is structural (which .LIB section a definition lives in), not a full HSPICE corner-value evaluation — it does not compute the numerically effective parameter values of a simulator run.

Diagnostics

Warnings (yellow squiggle) for:

• Unknown subcircuit — an X instance references a name not found in the file or its include graph.
• Port-count mismatch — an X instance provides a different number of nodes than its .SUBCKT declares ports.

Design notes & limitations

• Case-insensitive symbol lookup (HSPICE semantics); original case is preserved for display.
• HSPICE +, Spectre end-of-line \\, and Spectre { ... } continuations preserve physical token ranges during parsing.
• .param variable references inside expressions are extracted by scanning identifiers and excluding function calls (name(), user .func names, scientific-notation exponent markers, and HSPICE built-in functions (max, pwr, agauss, v, i, …). This covers .param values, model-card key='expr' values, and X/device/Spectre instance parameter expressions. It is best-effort and may produce false positives/negatives; it affects only reference completeness, never jump correctness.
• Nested .SUBCKT definitions are not supported (not valid HSPICE syntax).
• The navigation engine is derived from HSPICE IntelliSense (MIT) and substantially extended; see LICENSE (Third-Party Notice) and src/ file headers.

Supported File Extensions

.ckt, .sp, .net, .cir, .scs, .mod, .mdl, .lib, .sub, .l (HSPICE process library), .lis (SPICE output listing), .dspf (DSPF parasitic netlist)

Roadmap

• [x] 0.4.0 scope-local net Highlight / Peek / Hover / clickable Inlay Hints
• [ ] 0.5.0 workspace-scale symbol navigation, cancellable scanning, dialect/file configuration, and stronger cache invalidation
• [ ] 0.6.0 root-netlist-aware global and one-level connectivity, only after repeated demand and an unambiguous root context
• [ ] More snippet coverage
• [x] .param variable references from inside X-instance / device / Spectre instance parameter expressions
• [x] Spectre (.scs) navigation — added in 0.3.5 (Go-to-Definition / Hover / References / Outline / include links / section scope)

Contributing

1. Fork it ( https://github.com/lxTHU/vscode-spice )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Change Log

See CHANGELOG.md for the full history. Recent highlights:

• [0.4.0] Add scope-local net connectivity through native Highlight, References, Hover, F12, and clickable Inlay Hints; add Spectre \\ continuation and privacy-safe release gates.
• [0.3.9] Pin the reproducible toolchain, add CI/package gates, and fix multi-line parameter ranges plus two-node Spectre model navigation.
• [0.3.8] Add exact .param references inside model-card and instance/device parameter expressions.
• [0.3.7] Fix expression identifier boundaries so F12 fallback resolves operator-adjacent params like a-noiseflagn / (-noiseflagn) to noiseflagn.
• [0.3.6] Fix expression reference extraction for scientific notation and user .func names.
• [0.3.5] Spectre (.scs) navigation: Go-to-Definition / Hover / References / Outline / include links / section scope now work on Spectre model libraries too, including mixed-dialect files. New docs/SYNTAX.md compares the two dialect families.
• [0.3.1] Fix .lib dual-syntax (definition vs file reference) — the root cause of navigation failure on large PDK files. Add .param variable navigation, .LIB section navigation, section-scope resolution (auto + manual), and hierarchical Outline.
• [0.3.0] Add IDE-style netlist navigation: Go to Definition, Hover, Find References, Outline, Diagnostics, and .INCLUDE file links. Runs in-process (no language server).
• [0.2.4] Fix .lib / .model folding semantics; add .l extension.
• [0.2.3] Fix .model folding; add .enddata highlight, .lis / .dspf extensions, Spectre snippets.
• [0.2.1] Fix code folding for all block structures; improve scientific/engineering notation highlighting.
• [0.1.0] Add basic snippets support (ref bzisjo's great work).
• [0.0.6] Fix toggle-comment bug (Ctrl+/ adds * comment toggle).

License

MIT — Copyright (c) 2022-2026 Xuan Li, Wiener Technology, Beijing. See LICENSE.