lsp

Overview ¶

Decorator-arg/name LSP completions: dispatcher, context detection, error categories.

Import path + package-decl LSP completions.

Token-level helpers: duration/size unit completions + keyword list + extend-service context.

Type/decl LSP completions: project-wide decls + service/middleware/security/enum-value lookups.

Package lsp implements the CraftGo Language Server Protocol surface.

The server speaks LSP over stdio (a jsonrpc2.Stream wrapped around the caller's io.Reader / io.Writer) and forwards each open document through the existing parser + semantic analyser. Diagnostics published by the server are exactly the diagnostics the CLI would emit for the same source, so editor and CLI behaviour stay aligned by construction.

Currently supported:

• initialize / initialized / shutdown / exit lifecycle
• textDocument/didOpen / didChange / didSave / didClose
• textDocument/publishDiagnostics on every successful parse pass
• textDocument/hover (decorator, type ref, builtin docs)
• textDocument/completion (decorators, types, fields)
• textDocument/definition (cross-file decl resolution)
• textDocument/references (find all uses)
• textDocument/documentSymbol (outline)
• textDocument/formatting (canonical re-print via internal/format)
• textDocument/rename (declarations + every reference)

Any other request returns jsonrpc2.ErrMethodNotFound, which clients treat as "feature unsupported".

UTF-16 ↔ internal position conversion. The LSP protocol measures Position.Character in UTF-16 code units, whereas craftgo's lexer counts runes (Position.Column) and bytes (Position.Offset). A character in the Basic Multilingual Plane (<= U+FFFF) is one UTF-16 unit; a supplementary character (emoji, rare CJK, ...) is a surrogate PAIR — two units. Every crossing between an editor position and an internal position therefore has to go through these helpers, or columns drift on any line that carries multi-byte UTF-8 (byte ≠ rune) or supplementary runes (rune ≠ UTF-16).