SplitScript for Visual Studio Code

Write statically typed autosplitters with diagnostics, completion, navigation, documentation, formatting, and one-click WebAssembly builds. The extension contains the SplitScript compiler and language server, so it does not require a separate native executable.

Start a script

Install the SplitScript Marketplace pre-release. To test the newest verified master build instead, download the latest SplitScript VSIX and install it with Extensions: Install from VSIX. These early packages may contain breaking language changes.
Open a folder and create a saved file ending in .split.
Run SplitScript: Open Documentation and open Getting started. That compiler-checked guide introduces process attachment, a typed setting, one memory field, old / current snapshots, and the first timer decision.
On desktop, use Auto Splitter Debugger: Debug Active File to compile and run a .split source or directly launch a .wasm module inside VS Code. The debugger hot reloads saved .split sources and rebuilt .wasm modules by default. The dedicated Auto Splitter Debugger sidebar shows the simulated timer, runtime statistics, user settings, the raw settings map, timer variables, and controls; runtime output is sent to the Auto Splitting Runtime Output channel and Debug Console.
Use SplitScript: Start Debug Watch when you only want to continuously rebuild a .wasm file without launching it.
Use SplitScript: Build Release when the module is ready to distribute.

Both build commands create a .wasm file beside the source file. For example, game.split produces game.wasm. A failed or superseded build leaves the last successful module intact.

SplitScript generates a module for the Auto Splitting Runtime ABI. Selecting or installing that module is handled by the autosplitting host, not this extension. Use the host's normal local-Wasm workflow to load the generated file.

Commands

Command	Result
SplitScript: Open Documentation	Opens the compiler-owned reference index beside the active script.
SplitScript: Open Documentation for Current Symbol	Opens the exact language or standard-library page for the symbol at the caret. Assign it a shortcut through Keyboard Shortcuts for quick reference navigation.
SplitScript: Search Documentation	Searches symbols, concepts, signatures, summaries, and migration terms.
SplitScript: Start Debug Watch	Saves and builds the active script with the debug profile, then rebuilds it after later saves.
SplitScript: Stop Debug Watch	Stops the watcher shown in the status bar.
Auto Splitter Debugger: Debug Active File	Compiles an active `.split` source or directly runs an active `.wasm` module in an isolated Node WebAssembly worker, hot reloading either input by default. If neither is active, prompts for one.
Auto Splitter Debugger: Restart	Recompiles or rereads and replaces the running WebAssembly instance.
Auto Splitter Debugger: Start/Reset Timer	Controls the debugger's simulated timer.
Auto Splitter Debugger: Clear Settings Map	Removes all values currently overridden in the runtime settings map.
Auto Splitter Debugger: Reset Statistics	Clears collected tick timings while leaving the auto splitter running.
Auto Splitter Debugger: Open WebAssembly Memory	Opens linear memory through lazily loaded Debug Adapter Protocol pages in VS Code's Hex Editor.
Auto Splitter Debugger: Open Process Memory	Selects a starting mapping and opens a process-wide lazy memory view in the Hex Editor.
Auto Splitter Debugger: Show Logs	Opens the runtime Output channel.
SplitScript: Build Release	Saves and performs one optimized build of the active script.
SplitScript: Restart Language Server	Replaces the language-service worker without reloading the editor window.

Documentation and build commands are available from the Command Palette. The documentation and release-build actions also appear in the .split editor title; symbol documentation and build/watch actions are in the editor context menu.

Language support

The extension provides:

diagnostics with related source locations and quick fixes;
context-sensitive completion and signature help;
hover, inferred-type hints, semantic highlighting, and document symbols;
go to definition, references, rename, and selection ranges;
whole-document formatting, including Format on Save;
compiler-owned language, lifecycle, migration, and standard-library pages.

Formatting follows ancestor .editorconfig files by default. SplitScript uses indent_style, indent_size / tab_width, max_line_length, end_of_line, and insert_final_newline. The SplitScript › Formatting settings can override each choice for the editor without requiring an .editorconfig; an unset setting continues to inherit the file, editor, or formatter default.

The language server and build worker use separate compiler instances. A long or failed build therefore does not replace the language server. Source and output files are accessed through the VS Code workspace filesystem, including in virtual workspaces.

Requirements and current limits

VS Code 1.125 or newer is required.
The extension supports desktop and browser extension hosts.
Running an autosplitter is currently a desktop-only capability and requires a trusted local workspace. Browser, virtual, and untrusted workspaces retain the compiler and language tooling.
The debugger implements the complete timer, runtime, process, user-settings, and settings map/list/value ASR APIs. Native process attachment, liveness, module lookup, mapped ranges, and read-only memory access run in a Rust N-API bridge; attached processes appear in Processes. Each open process has an inline memory action that queries its readable mapped ranges on demand and opens a process-wide lazy view at the selected range's base without copying the entire process. Release VSIX packages include native bridges for Windows x64, Linux x64 and ARM64, and macOS Intel and Apple Silicon. Autosplitter ticks run at the requested rate independently of sidebar snapshots, which are coalesced to at most five updates per second. The Statistics panel keeps a bounded window of 2,048 tick timings and provides reset and lazy Wasm-memory actions without stopping the runtime. On macOS, attaching to another process uses task_for_pid and is subject to the operating system's debugger authorization and target code-signing rules. A denied attachment reports that permission boundary explicitly.
WASI snapshot preview1 (WASI 0.1) is available with a read-only filesystem below /mnt. Arguments and environment variables are deliberately empty, and filesystem-mutating operations return NOTCAPABLE.
Source breakpoints and stepping are not implemented yet. Debug builds already carry source and variable metadata; pausing V8 execution requires the planned debugger-instrumented compiler mode.
A directly launched .wasm file is instantiated as-is. Modules exporting update use the recurring auto-splitting loop; otherwise _initialize and _start are invoked once when present. A module with no conventional entry point still runs its WebAssembly start section during instantiation.
Building requires a saved .split resource and write access beside it.
Generated modules require an autosplitting host with WebAssembly GC enabled. Older host engines that disable WebAssembly GC cannot instantiate them.
The debugger uses a simulated timer and does not control a running LiveSplit instance.
Version 0.1.x is distributed through the Visual Studio Marketplace's opt-in pre-release channel.

Troubleshooting

If a build fails, open SplitScript Compiler in the Output panel and inspect the source diagnostics in Problems. Fixing the source and saving it is enough to retry an active debug watch.

If hover, completion, highlighting, and navigation all stop together, run SplitScript: Restart Language Server. If the problem is reproducible, keep the smallest source that triggers it and the language-server output so it can be reported without losing the failing state.

If a build targets the wrong file, make sure the intended .split editor is active when starting the command. Untitled files prompt for a save location; the resulting saved document is the one compiled.

SplitScript