fish-lsp

Introducing the fish-lsp, a Language Server Protocol (LSP) implementation for the fish shell language.

Why? 🐟

🦈 Efficiency: enhances the shell scripting experience with an extensive suite of intelligent text-editing features
🐡 Flexibility: allows for a highly customizable configuration
🐚 Guidance: friendly hints and documentation to comfortably explore command line tooling
🐬 Community: improved by a vibrant user base, with supportive and insightful feedback
🐙 Compatibility: integrates with a wide variety of tooling and language clients
🌊 Reliability: produces an editor agnostic developer environment, ensuring all fish user's have access to a consistent set of features

Features

Feature	Description	Status
Completion	Provides completions for commands, variables, and functions	✅
Hover	Shows documentation for commands, variables, and functions. Has special handlers for `--flag`, `commands`, `functions`, `variables`	✅
Signature Help	Shows the signature of a command or function	✅
Goto Definition	Jumps to the definition of a command, variable, or function	✅
Find References	Shows all references to a command, variable, or function	✅
Rename	Rename within matching global && local scope	✅
Document Symbols	Shows all commands, variables, and functions in a document	✅
Workspace Symbols	Shows all commands, variables, and functions in a workspace	✅
Document Formatting	Formats a document, full & selection	✅
Document Highlight / Semantic Token	Highlights all references to a command, variable, or function.	✅
Command Execution	Executes a server command from the client	✅
Code Action	Shows all available code actions	✖
Code Lens	Shows all available code lenses	✖
Logger	Logs all server activity	✅
Diagnostic	Shows all diagnostics	✅
Folding Range	Toggle ranges to fold text	✅
Telescope Integration	Integrates with the telescope.nvim plugin	✅
CLI Interactivity	Provides a CLI for server interaction. Built by `fish-lsp complete <option>`	✅
Client Tree	Shows the defined scope as a Tree	✅
Indexing	Indexes all commands, variables, and functions	✅

Installation

Recommended Dependencies: yarn@1.22.22, node@21.7.1, fish@3.7.1

Building from source is the only currently recommended installation method, as we improve other methods of the installation process (Don't use releases or npm packages). Contributions to help enhance installation options are greatly appreciated!

Clone the repo

git clone https://github.com/ndonfris/fish-lsp
# cd fish-lsp

Install the dependencies & run the setup handler scripts
```
yarn install
```
Optional: Check that the project successfully compiled & linked
```
fish-lsp --help # ./bin/fish-lsp --help
```

Setup

To properly configure fish-lsp, you need to define a client configuration after installing the language server. Client's typically only need the keys command, args/arguments, and filetypes to start a language server.

Client Configuration (Required)

Theoretically, the language-server should generally be compatible with almost any text-editor or IDE you prefer using. Feel free to setup the project in any fish-lsp-client of your choice, or submit a PR for new configurations.

{
  "fish-lsp": {
    "command": "fish-lsp",
    "filetypes": ["fish"],
    "args": ["start"]
  }
}

Neovim client using coc.nvim configuration, located inside coc-settings.json "languageserver" key

Server Configuration (Optional)

Specific functionality for the server can be set independently from the client. This allows for multiple configurations, to be defined and chosen via specific startup requirements (i.e., using the bind command with the function edit_command_buffer).

Environment variables

Generated by fish-lsp env --create

# fish_lsp_enabled_handlers <ARRAY>
# enables the fish-lsp handlers (options: 'formatting', 'complete', 'hover', 'rename', 'definition', 'references', 'diagnostics', 'signatureHelp', 'codeAction', 'index')
set -gx fish_lsp_enabled_handlers

# fish_lsp_disabled_handlers <ARRAY>
# disables the fish-lsp handlers (options: 'formatting', 'complete', 'hover', 'rename', 'definition', 'references', 'diagnostics', 'signatureHelp', 'codeAction', 'index')
set -gx fish_lsp_disabled_handlers

# fish_lsp_commit_characters <ARRAY>
# array of the completion expansion characters. Single letter values only.
# Commit characters are used to select completion items, as shortcuts. (default: [])
set -gx fish_lsp_commit_characters

# fish_lsp_logfile <STRING>
# path to the logs.txt file (default: '')
# example locations could be: '~/path/to/fish-lsp/logs.txt' or '/tmp/fish_lsp_logs.txt'
set -gx fish_lsp_logfile

# fish_lsp_format_tabsize <NUMBER>
# amount of spaces in a tab character for the formatter provider (default: 4)
set -gx fish_lsp_format_tabsize

# fish_lsp_format_switch_case <BOOLEAN>
# keep case statements left aligned with switch block. (default: false)
set -gx fish_lsp_format_switch_case

# fish_lsp_all_indexed_paths <ARRAY>
# fish file paths/workspaces to include as workspaces (default: ['/usr/share/fish', "$HOME/.config/fish"])
set -gx fish_lsp_all_indexed_paths

# fish_lsp_modifiable_paths <ARRAY>
# fish file paths/workspaces that can be renamed by the user. (default: ["$HOME/.config/fish"])
set -gx fish_lsp_modifiable_paths

# fish_lsp_diagnostic_disable_error_codes <ARRAY>
# disable diagnostics for matching error codes (default: [])
# (options: 1001, 1002, 1003, 1004, 2001, 2002, 2003, 3001, 3002, 3003)
set -gx fish_lsp_diagnostic_disable_error_codes

# fish_lsp_max_background_files <NUMBER>
# maximum number of background files to read into buffer on startup (default: 1000)
set -gx fish_lsp_max_background_files

# fish_lsp_show_client_popups <BOOLEAN>
# show popup window notification in the connected client (default: true)
set -gx fish_lsp_show_client_popups

Command Flags

Both the flags --enable and --disable are provided on the fish-lsp start subcommand. By default, all handlers will be enabled.

# displays what handlers are enabled. Removing the dump flag will run the server.
fish-lsp start --disable complete signature --dump

Further Server Configuration

Any flags will overwrite their corresponding environment variables, if both are seen for the fish-lsp process. For this reason, it is encouraged to wrap any non-standard behavior of the fish-lsp in functions or aliases.

Due to the vast possibilities this project aims to support in the fish shell, sharing useful configurations is highly encouraged.

How does it work?

If you're new to the concept of the Language Server Protocol (LSP), this section should be useful to help you grasp its core purpose and benefits.

📸 Check out this insightful video by TJ DeVries for an introduction to the subject.

The LSP is designed to create a uniform approach for supporting a programming language across various development tools, moving beyond the confines of specific Text-Editor/IDE ecosystems. This standardization enhances a language's appeal by allowing developers to maintain consistent tooling support without needing to switch developer environments.

The core of this system is the interaction between a 'language server', which provides language services, and a 'language client', which consumes these services. The protocol facilitates this interaction, ensuring that any language client can leverage a well-defined set of features provided by the server.

Show a diagram to visualize a hypothetical fish-lsp process

![graph](https://github.com/ndonfris/fish-lsp.dev/blob/master/public/mermaid-diagram.png?raw=true)

Additional Resources

Contributing - documentation describing how to contribute to the fish-lsp project.
Roadmap - goals for future project releases.
Wiki - further documentation and knowledge relevant to the project
Discussions - interact with maintainers
Site - website homepage
Client Examples - testable language client configurations
Sources - major influences for the project