#moonbit-spice

moonbit-spice is a reusable SPICE-like circuit analysis library written in MoonBit. It turns a readable netlist into a validated circuit model, assembles modified nodal analysis (MNA) equations, solves the operating point, and emits structured results for teaching tools, design utilities, scripts, and future WASM front ends.

#Core capabilities

SPICE-like parsing with blank lines, comments, directives, duplicate-name detection, and engineering suffixes (k, meg, m, u, n, p).
Resistors, capacitors, inductors, diodes, independent current sources, and independent voltage sources.
Dense MNA with partial pivoting, residual diagnostics, singular-system reporting, deterministic node ordering, and circuit topology inventory.
DC operating-point analysis with explicit warnings for DC approximations.
Reusable matrix/vector utilities, time grids and integration primitives, deterministic parameter sweeps, complex-value helpers, and result reports.
CSV, text, and Markdown output that can be consumed by a CLI or a notebook.

The implementation is intentionally explicit about model boundaries. AC and full nonlinear/transient circuit solves are represented by extension points and small reusable kernels; the library does not fabricate results for analyses it does not yet solve physically.

#Quick start

let circuit = @spice.parse_netlist(
  "V1 in 0 10\nR1 in out 1k\nR2 out 0 1k",
)
let result = @spice.dc(circuit)
println(result.summary())

From the repository root:

moon fmt --check
moon check --deny-warn
moon test --deny-warn
moon run cmd/spice

The sample input is also available at examples/voltage-divider.cir.

#CLI

moon run cmd/spice runs a deterministic voltage-divider smoke example and prints a Markdown report. It is deliberately dependency-free so a fresh MoonBit checkout can run it without a package manager or native runtime library.

The library API is the stable integration surface. Applications can read a file, call parse_netlist, choose dc or analyze, and serialize with report_csv, report_markdown, or SimulationResult::summary.

#Architecture

netlist text
    -> parser and validation
    -> Circuit / Device model
    -> MNA stamping
    -> DenseMatrix + MatrixSolver
    -> SimulationResult
    -> CSV / text / Markdown report

The src/ package keeps public data structures and the analysis boundary in one place. Matrix, topology, sweep, transient, complex-value, reporting, and benchmark utilities are split into focused files so callers can reuse the smallest useful unit.

#Benchmarks

The reproducible fixtures and commands live in benchmarks/. They measure the real parser, MNA, topology, and formatting path. Run:

Measure-Command { moon test --deny-warn }
moon run cmd/spice

Timings depend on the host and toolchain. CI stores the command output as an artifact instead of presenting an unrepeatable number as a universal claim.

#Tests and boundary coverage

Tests cover voltage-divider and current-source solutions, suffix parsing, duplicate devices, result exports, matrix residuals, topology connectivity, ordered sweeps, invalid transient grids, and Markdown report metadata. The stricter local gate is:

moon fmt --check
moon check --deny-warn
moon test --deny-warn
moon info

#CI

GitHub Actions runs the current MoonBit installer on Ubuntu, macOS, and Windows. It checks all targets, formatting, public interface generation, warnings, tests, and the CLI smoke path. A separate workflow records deterministic benchmark artifacts. See .github/workflows/ci.yml.

#License

Released under the MIT License. The project is an independent MoonBit implementation. The example circuits are small educational fixtures and do not include copied third-party source or proprietary model files.

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