SystemVerilog Formatter

Opinionated, production-tested auto-indent formatter for SystemVerilog (.sv, .svh). Built and hardened against real UVM/DV codebases — not toy examples — across months of iteration on constructs that commonly break generic formatters.

Why this formatter

Most generic indenters choke on SystemVerilog's ambiguous constructs. This one is built specifically to get them right:

begin/end matching, including deeply nested dangling if/else chains with no explicit begin/end.
do...while loops, fork/join/join_none/join_any.
randomize() with { ... } constraint blocks.
Preprocessor `ifdef/`elsif/`else/`endif chains sharing a single trailing begin.
`pragma protect begin/`pragma protect end and `protect/`endprotect regions — preserved without disturbing surrounding indentation.
Multi-line if (... inside {...}) begin and other tricky continuations.

Features

One-command formatting — wire it up as your default formatter and use Format Document (or Format on Save) like any other language.
Configurable begin style — same line (K&R) or its own line (Allman), switchable instantly from Settings.
Configurable indent width — 1 to 8 spaces per level.
Zero external dependencies. The formatting engine ships as a single, statically linked binary bundled inside the extension — no Python, no runtime to install, no glibc version requirements.
Works entirely over stdin/stdout — no temporary files ever touched on disk.

Getting started

Install the extension.
Open a .sv or .svh file.
Run Format Document (Shift+Alt+F / Ctrl+Shift+I), or set it as your default formatter with Format on Save:

{
  "[systemverilog]": {
    "editor.defaultFormatter": "quindeptrai.systemverilog-formatter",
    "editor.formatOnSave": true
  }
}

Settings

Setting	Default	Description
`svFormatter.beginStyle`	`same`	`same` = `begin` on the same line as the block header (K&R). `next` = `begin` on its own line (Allman).
`svFormatter.indentSize`	`4`	Spaces per indentation level.

Open Settings (Ctrl+,), search for SystemVerilog Formatter, and change values there — no restart needed, just re-run Format Document.

Example

svFormatter.beginStyle: "same" (default)

if (rw.kind == UVM_READ) begin
    rd_wr_t = 1;
end
else begin
    rd_wr_t = 0;
end

svFormatter.beginStyle: "next"

if (rw.kind == UVM_READ)
begin
    rd_wr_t = 1;
end
else
begin
    rd_wr_t = 0;
end

Requirements

The formatting engine ships as a fully self-contained, statically linked binary — no separate runtime, no system libraries, no glibc version dependency at all.

OS: Linux
CPU: x86_64

No Windows, macOS, or ARM support in this build.

Remote workspaces (SSH)

The extension is marked as a workspace extension (extensionKind: ["workspace"]), so with Remote-SSH it always installs and runs on the remote server automatically — never on your local machine. Just install it while connected; no extra setup needed, as long as the remote server meets the requirements above.

Known limitations

Formats the whole document; range/selection formatting is not yet supported.
Designed for UVM-style RTL/testbench code; extremely unusual macro usage may need manual touch-ups.

Contributing

Issues and pull requests are welcome — see CONTRIBUTING if present, or open an issue directly.

Release Notes

See CHANGELOG.md.

License

MIT