Editors

VS Code

Install from the Visual Studio Marketplace.

Neovim

See setup instructions in the README.

Sublime Text

Install LSP-wren-lsp from Package Control.

Configuration

Place a wren-lsp.json in your project root. The server searches upward from each opened file to find it.

{
  "version": 1,
  "extends": ["~/.config/wren-lsp/base.json"],
  "modules": [
    "./src",
    "./lib",
    { "game": "./src/game.wren" }
  ],
  "resolvers": [
    { "type": "path", "roots": ["./src"], "delimiter": "/" },
    { "type": "plugin", "library": "./resolver" }
  ],
  "diagnostics": {
    "missing_import": "warning",
    "extension_in_import": "info",
    "unknown_variable": "error"
  }
}

version

Schema version. Currently 1.

extends

Paths to parent configs. Later entries override earlier ones.

modules

Where to find Wren files. Each entry is either:

• A directory path to scan for .wren files
• A named mapping like { "name": "path" } for specific modules

resolvers

How imports are resolved. Tried in order until one matches.

path

Treats imports as file paths. Options: roots, delimiter.

{
  "type": "path",
  "roots": ["./src", "./lib"],
  "extensions": [".wren"],
  "indexFiles": ["mod.wren", "init.wren"]
}

plugin

Loads a shared library for custom resolution. See Plugins.

{
  "type": "plugin",
  "library": "./my-resolver"
}

diagnostics

Severity for each diagnostic. Values: error, warning, info, hint, none.

missing_import

Import could not be resolved. Default: warning.

extension_in_import

Import includes .wren extension. Default: info.

unknown_variable

Variable not found in scope. Default: error.

Plugins

Plugins are shared libraries that resolve imports using custom logic. Useful for game engines or frameworks with their own module systems.

The library path should omit the extension—it is added automatically (.so, .dylib, .dll).

C Interface

Your library must export two functions with C linkage:

typedef struct {
    const char* severity;  // "error", "warning", "info", "hint"
    const char* message;
} WrenLspDiagnostic;

typedef struct {
    const char* canonical_id;  // required if resolved
    const char* uri;           // file:// URI or null
    const char* source;        // virtual source or null
    const char* kind;          // "file", "virtual", or "remote"
    WrenLspDiagnostic* diagnostics;
    size_t diagnostics_len;
} WrenLspResolveResult;

WrenLspResolveResult wren_lsp_resolve_module(
    const char* importer_uri,
    const char* import_string,
    const char* project_root
);

void wren_lsp_free_result(WrenLspResolveResult result);

Parameters

importer_uri

File URI of the importing file.

import_string

The import string to resolve.

project_root

Absolute path to the project root.

Return Value

Set canonical_id to the resolved module identifier. Return null to indicate the import could not be resolved.

Set kind to "file" and uri to the file path.

The LSP calls wren_lsp_free_result after processing, so you can free any memory allocated for the result.