YAPLSPD — Yet Another Perl Language Server Protocol Daemon

Deutsche Version: README_DE.md

A complete Perl Language Server Protocol (LSP) daemon written in pure Perl.

Features

Implemented LSP Features (22)

Feature	Method	Status
Autocompletion	textDocument/completion	✅
Hover Information	textDocument/hover	✅
Go to Definition	textDocument/definition	✅
Find References	textDocument/references	✅
Document Symbols	textDocument/documentSymbol	✅
Code Formatting	textDocument/formatting	✅
Range Formatting	textDocument/rangeFormatting	✅
Signature Help	textDocument/signatureHelp	✅
Rename	textDocument/rename	✅
Code Actions	textDocument/codeAction	✅
Folding Ranges	textDocument/foldingRange	✅
Document Highlight	textDocument/documentHighlight	✅
Code Lens	textDocument/codeLens	✅
Selection Range	textDocument/selectionRange	✅
Workspace Symbols	workspace/symbol	✅
Configuration	workspace/didChangeConfiguration	✅
File Watching	workspace/didChangeWatchedFiles	✅
Document Sync	textDocument/didOpen/didChange/didClose	✅
Diagnostics	textDocument/publishDiagnostics	✅
Call Hierarchy	textDocument/prepareCallHierarchy, callHierarchy/*	✅
Type Hierarchy	textDocument/prepareTypeHierarchy, typeHierarchy/*	✅
Semantic Tokens	textDocument/semanticTokens/full, textDocument/semanticTokens/range	✅

YAPLSPD vs. Competition

Feature	YAPLSPD	Perl::LS	PLS	Navigator
completion	✅	✅	✅	✅
hover	✅	✅	✅	✅
definition	✅	✅	✅	✅
references	✅	✅	✅	✅
documentSymbol	✅	✅	✅	✅
formatting	✅	✅	✅	✅
rangeFormatting	✅	✅	✅	✅
signatureHelp	✅	✅	❌	✅
rename	✅	✅	⚠️	✅
codeAction	✅	❌	❌	⚠️
foldingRange	✅	✅	❌	✅
documentHighlight	✅	✅	❌	✅
codeLens	✅	❌	❌	❌
selectionRange	✅	❌	❌	✅
workspace/symbol	✅	✅	✅	✅
workspace/configuration	✅	✅	✅	✅
callHierarchy	✅	❌	❌	⚠️
typeHierarchy	✅	❌	❌	⚠️
semanticTokens	✅	❌	❌	✅
Pure Perl	✅	⚠️ (XS)	✅	❌ (Node.js)

Installation

Requirements

• Perl 5.20 or higher
• cpanm (App::cpanminus)

Dependencies

# Automatic installation of all dependencies
cpanm --installdeps .

Manual installation of core dependencies:

• JSON::PP (core module)
• PPI - Perl parsing
• Perl::Tidy - Code formatting

Installing YAPLSPD

git clone https://github.com/ghbalf/yaplspd.git
cd yaplspd
cpanm --installdeps .

Editor Setup

Neovim

With nvim-lspconfig:

local lspconfig = require('lspconfig')
local configs = require('lspconfig.configs')

if not configs.yaplspd then
  configs.yaplspd = {
    default_config = {
      cmd = {'/path/to/yaplspd/bin/yaplspd'},
      filetypes = {'perl'},
      root_dir = function(fname)
        return lspconfig.util.find_git_ancestor(fname)
      end,
    },
  }
end

lspconfig.yaplspd.setup{}

With vim-lsp:

if executable('yaplspd')
    au User lsp_setup call lsp#register_server({
        \ 'name': 'yaplspd',
        \ 'cmd': {server_info->['/path/to/yaplspd/bin/yaplspd']},
        \ 'whitelist': ['perl'],
        \ })
endif

VS Code

Create .vscode/settings.json in your project root:

{
  "perl.perlCmd": "perl",
  "perl.perlInc": ["lib", "local/lib/perl5"],
  "perl.trace.server": "verbose",
  "perl.debugAdapter": "null"
}

For direct YAPLSPD integration, install the extension and configure:

{
  "perl.languageServer": "/path/to/yaplspd/bin/yaplspd",
  "perl.languageServerEnabled": true
}

Emacs

With lsp-mode:

(require 'lsp-mode)

(add-to-list 'lsp-language-id-configuration '(perl-mode . "perl"))
(add-to-list 'lsp-language-id-configuration '(cperl-mode . "perl"))

(lsp-register-client
 (make-lsp-client :new-connection (lsp-stdio-connection '("/path/to/yaplspd/bin/yaplspd"))
                  :major-modes '(perl-mode cperl-mode)
                  :server-id 'yaplspd))

Usage

Starting the Server

# Direct
./bin/yaplspd

# With logging
PERL_YAPLSPD_LOG=1 ./bin/yaplspd 2>/tmp/yaplspd.log

Running Tests

# All tests
prove -lr t

# With verbose output
prove -lvr t

# Single test file
prove -l t/completion.t

Code Formatting

# Format project
perltidy lib/**/*.pm

Architecture

lib/YAPLSPD/
├── Server.pm            # Main server (LSP protocol)
├── Protocol.pm          # LSP protocol handler
├── Document.pm          # Document management (PPI)
├── Completion.pm        # Autocompletion
├── Hover.pm             # Hover information
├── Definition.pm        # Go-to-definition
├── References.pm        # Find-all-references
├── DocumentSymbol.pm    # Document symbols (outline)
├── Formatting.pm        # Code formatting (Perl::Tidy)
├── Diagnostics.pm       # Syntax diagnostics
├── SignatureHelp.pm     # Function signatures
├── Rename.pm            # Symbol renaming
├── CodeAction.pm        # Quick-fixes & refactorings
├── FoldingRange.pm      # Code folding
├── DocumentHighlight.pm # Symbol highlighting
├── CodeLens.pm          # Code lenses (references, tests)
├── SelectionRange.pm    # Smart selection
├── WorkspaceSymbol.pm   # Workspace-wide symbol search
├── CallHierarchy.pm     # Incoming/outgoing call analysis
├── TypeHierarchy.pm     # Super-/subtype analysis
├── SemanticTokens.pm    # Semantic highlighting tokens
├── ParallelParsing.pm   # Workspace parsing for larger projects
└── MemoryManager.pm     # LRU-based document memory management

Project Status

Completed

• Core LSP protocol
• 22 LSP features implemented
• E2E integration tests
• Call hierarchy
• Type hierarchy
• Semantic tokens
• Parallel parsing for larger workspaces
• Memory management for long-running sessions
• README + README_DE + MIT license
• GitHub release v0.7.0
• 293 tests passing

Current Notes

• Pure Perl implementation (no XS requirement for core functionality)
• Optional PPI-backed parsing with regex fallback paths for resilience
• Some test runs emit warnings in older modules, but the full suite currently passes

Troubleshooting

"Can't locate PPI.pm"

cpanm PPI

Server won't start

Check the logs:

PERL_YAPLSPD_LOG=1 ./bin/yaplspd 2>&1 | tee /tmp/yaplspd.log

No autocompletion

Make sure the lib/ directory is in @INC:

# In .vscode/settings.json or your editor config
"perl.perlInc": ["lib", "local/lib/perl5"]

License

MIT License — See LICENSE

Contributing

Pull requests welcome! Please:

1. Write tests for new features
2. Run perltidy before committing
3. Ensure existing tests pass: prove -lr t

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Disclaimer

This software was written by an AI. If that bothers you, feel free to close this tab and move on with your day. The code works either way.

Authors

• Siegfried Mickautsch (AI) — Author
• Alfred Mickautsch — Created by
• OpenClaw — Powered by

YAPLSPD — Because Perl deserves a modern LSP.