Language support for DRL (Drools Rule Language) files in Visual Studio Code, powered by a dedicated Language Server.

Requirements

Java 17 or later (JAVA_HOME must be set or java must be on your PATH)
Maven (for classpath resolution of Java types used in rules)

Features

Code Editing

Syntax highlighting
Code completion for grammar keywords, Java class names, fields/properties, and DRL declare types
Inlay hints for bound variables
Live class index refresh on recompile (no server restart required)

Go-to definition for DRL and Java types
Find references for DRL types and bound variables
Rename for DRL declared types and bound variables
Document symbols (outline view)
Type hierarchy for DRL types
Folding ranges for DRL blocks and comments

Diagnostics

Syntax error reporting
Lint diagnostics (missing end, missing separators, unbalanced parentheses, etc.)
Unknown-type lint with typo quick-fix for DRL-declared types

Information

Hover tooltips for DRL/Java types with doc-comment rendering
Reference-count code lens for DRL declared types

Extension Settings

Setting	Default	Description
`drools.lsp.logLevel`	`INFO`	Server-side log level
`drools.lsp.lint.missingEnd`	`warning`	Severity for missing `end` keyword
`drools.lsp.lint.missingSeparator`	`warning`	Severity for missing constraint separator
`drools.lsp.lint.missingSemicolon`	`warning`	Severity for missing semicolon in consequence
`drools.lsp.lint.unbalancedParens`	`warning`	Severity for unbalanced parentheses
`drools.lsp.lint.mvelPropertyAccess`	`off`	Hint to prefer property-access style over getter calls in LHS
`drools.lsp.inlayHints.enabled`	`true`	Show inline type hints for bound variables
`drools.lsp.maven.pomPath`	`""`	Maven POM path(s) for classpath resolution

All lint settings accept: off, hint, info, warning, error.

Some features can be further configured using VS Code's built-in settings, such as editor.inlayHints.enabled for inlay hint visibility and editor.folding for folding range behavior.