Overview

• lsp-mode = Language server protocol mode
• Spec created by Microsoft in conjunction with VSCode
  • https://github.com/Microsoft/language-server-protocol
  • Started in 2015
  • Now on version 3.15
• Provides an abstraction by which IDE features are available via requests made to a language server using JSON-RPC

(https://microsoft.github.io/language-server-protocol/overviews/lsp/overview/)

• Major features of spec - support for:
  • Code completion
  • “Hover” (Documentation and context information)
  • Jump to definition
  • Workspace symbols
  • Diagnostics (Linting)
• One mode to rule them all!
  • Provides powerful IDE features for any language with a language server implementation
  • Instead of every editor having to implement support for each language

(https://langserver.org/#implementations-client)

• Lots of server implementations available
  • For instance for Python - microsoft/python-language-server, palantir/python-language-server and sourcegraph/python-langserver
  • Comprehensive overview is available here
• Supported by lots of editors as well (see here)
• Language servers are frequently just an (opinionated) combination of community tools
  • For instance, palantir/python-language-server uses jedi, rope, pylint, mypy etc…

Demo

• All code and configurations available from https://github.com/cc-a/lsp-mode-demo

The Future

• Debug Adapter Protocol
• pylance

Links

• https://github.com/emacs-lsp/lsp-mode
• https://emacs-lsp.github.io/lsp-ui/
• https://langserver.org/
• https://github.com/emacs-lsp/lsp-docker