lsp

README

Ns LSP

ns lsp command implements language server protocol. It uses stdin/stdout as JSON-RPC2 medium.

The LSP can be used by various editors and IDEs. Notably fn-vscode extension plumbs this LSP into VSCode.

The LSP is implemented inside the ns binary to make sure that it editor integrations behave 100% consistent with the command line tools.

References

• Upstream tracking issue https://github.com/cue-lang/cue/issues/142
• LSP Specification https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/
• Cue Language specification https://cuelang.org/docs/references/spec/

Related work

• Cue LSP draft implementation https://github.com/galli-leo/cue-lsp-server/
• Go LSP framework https://github.com/go-language-server/jsonrpc2
• Go LSP type definitions https://github.com/sourcegraph/go-lsp/
• Another Go LSP framework https://github.com/TobiasYin/go-lsp/
• Private JSONRPC implementation https://pkg.go.dev/golang.org/x/tools/internal/jsonrpc2

Examples

• VSCode CUE syntax https://github.com/ngkcl/vscode-cuelang
• Abandoned 3p Golang LSP https://github.com/sourcegraph/go-langserver/blob/master/langserver/handler.go
• VSCode->Gopls integration https://github.com/golang/vscode-go/blob/master/src/language/goLanguageServer.ts
• VSCode LSP sample https://github.com/microsoft/vscode-extension-samples/tree/main/lsp-sample/

Documentation

Overview

Runs a Language Server Protocol (LSP) server ready to comminicate with any editor/IDE.

This command is not intended to be invoked by end-users directly. Instead respective editor plugins will manage the instances of LSP server as needed.

Index

• func NewLSPCmd() *cobra.Command
• func WriteOverlay(underlying fs.ReadDirFS) *writeOverlay
• type FnWorkspace
  • func (ws *FnWorkspace) AbsPathForPkgName(ctx context.Context, pkgName string) (string, error)
  • func (ws *FnWorkspace) AbsRoot() string
  • func (ws *FnWorkspace) EvalPackage(ctx context.Context, pkgName string) (cue.Value, error)
  • func (ws *FnWorkspace) FS() fs.ReadDirFS
  • func (ws *FnWorkspace) PkgNameInMainModule(relPath string) string
  • func (ws *FnWorkspace) SnapshotDir(ctx context.Context, pkgname schema.PackageName, opts memfs.SnapshotOpts) (*fncue.PackageContents, error)
• type OpenFiles
  • func NewOpenFiles() *OpenFiles
  • func (of *OpenFiles) DidChange(params *protocol.DidChangeTextDocumentParams) (err error)
  • func (of *OpenFiles) DidClose(params *protocol.DidCloseTextDocumentParams) (err error)
  • func (of *OpenFiles) DidOpen(params *protocol.DidOpenTextDocumentParams) (err error)
  • func (of *OpenFiles) Read(uri protocol.URI) (Snapshot, error)
• type Snapshot

Functions

func NewLSPCmd

func NewLSPCmd() *cobra.Command

func WriteOverlay

func WriteOverlay(underlying fs.ReadDirFS) *writeOverlay

Types

type FnWorkspace

type FnWorkspace struct {
	// contains filtered or unexported fields
}

Represents an Fn workspace with its partially-parsed Cue files. An Fn workspace is rooted in a directory with a `workspace.ns.textpb“ file. There may be multiple FnWorkspace's in an editor workspace. Roughly corresponds to a parsing.Root, schema.Workspace and [loader.PackageLoader].

func (*FnWorkspace) AbsPathForPkgName

func (ws *FnWorkspace) AbsPathForPkgName(ctx context.Context, pkgName string) (string, error)

Real filesystem path for the package name (example.com/module/package/file.cue). Supports external modules and may download them on-demand (hence [ctx]).

func (*FnWorkspace) AbsRoot

func (ws *FnWorkspace) AbsRoot() string

func (*FnWorkspace) EvalPackage

func (ws *FnWorkspace) EvalPackage(ctx context.Context, pkgName string) (cue.Value, error)

func (*FnWorkspace) FS

func (ws *FnWorkspace) FS() fs.ReadDirFS

func (*FnWorkspace) PkgNameInMainModule

func (ws *FnWorkspace) PkgNameInMainModule(relPath string) string

Take a relative path (package/file.cue) and returns a fully-qualified package name (example.com/module/package/file.cue) within the main workspace module.

func (*FnWorkspace) SnapshotDir

func (ws *FnWorkspace) SnapshotDir(ctx context.Context, pkgname schema.PackageName, opts memfs.SnapshotOpts) (*fncue.PackageContents, error)

type OpenFiles

type OpenFiles struct {
	// contains filtered or unexported fields
}

Implements LSP document sync protocol to maintain a view into currently open files. For the open files the authoritative content is stored in the editor memory instead of the filesystem. TODO: Implement delta sync.

func NewOpenFiles

func NewOpenFiles() *OpenFiles

func (*OpenFiles) DidChange

func (of *OpenFiles) DidChange(params *protocol.DidChangeTextDocumentParams) (err error)

func (*OpenFiles) DidClose

func (of *OpenFiles) DidClose(params *protocol.DidCloseTextDocumentParams) (err error)

func (*OpenFiles) DidOpen

func (of *OpenFiles) DidOpen(params *protocol.DidOpenTextDocumentParams) (err error)

func (*OpenFiles) Read

func (of *OpenFiles) Read(uri protocol.URI) (Snapshot, error)

type Snapshot

type Snapshot struct {
	Version int32
	Text    string
}