Skip to main content

FORTRAN Language Server for the Language Server Protocol

Project description

A Fortran implementation of the Language Server Protocol using Python (2.7+).

Editor extensions using this language server to provide autocomplete and other IDE-like functionality are available for Atom, Visual Studio Code, and (Neo)vim.

Note: This language server is currently in the early stages of development. Not all features are supported or planned.

Language Server Features

Document Symbols:

Auto Completion:

Signature Help:

Note: Not available for overloaded subroutines/functions.

Go to definition:


Find references:

Note: Currently for global and top level module objects only.


  • Multiple use of the same variable name
  • Unknown module in USE statement
  • Variable masking definition from parent scope


pip install fortran-language-server

Language server settings

The following global settings can be used when launching the language server.

  • --symbol_skip_mem Do not include type members in document symbol results
  • --incremental_sync Use incremental document synchronization (beta)
  • --autocomplete_no_prefix Do not filter autocomplete results by variable prefix
  • --lowercase_intrinsics Use lowercase for intrinsics and keywords in autocomplete requests
  • --use_signature_help Use signature help instead of snippets for subroutines/functions
  • --variable_hover Show hover information for variables (default: subroutines/functions only)

Debug settings:

The following settings can be used to perform standalone debug tests on the language server.

  • --debug_filepath=DEBUG_FILEPATH File path for language server tests
  • --debug_rootpath=DEBUG_ROOTPATH Root path for language server tests
  • --debug_line=DEBUG_FILEPATH Line position for language server tests (1-indexed)
  • --debug_char=DEBUG_ROOTPATH Character position for language server tests (1-indexed)
  • --debug_parser Test source code parser on specified file
  • --debug_symbols Test symbol request for specified file
  • --debug_completion Test completion request for specified file and position
  • --debug_signature Test signatureHelp request for specified file and position
  • --debug_definition Test definition request for specified file and position


Project specific settings can be specified by placing a JSON file named .fortls (example below) in the root_dir directory.

Setup module search paths:

By default all files with the suffix F,F77,F90,F95,F03,F08,FOR,FPP (case-insensitive) in the root_dir directory, specified during initialization, and all its sub-directories are parsed and included in the project.

Directories and files can be excluded from the project by specifying their paths (relative to root_dir) in the excl_paths variable in the .fortls file. Excluded directories also exclude all sub-directories.

Module directories can also be specified manually by specifying their paths (relative to root_dir) in the mod_dirs variable in the .fortls file. When mod_dirs is specified directories are not added recursively, so any nested sub directories must be explicitly listed. However, root_dir does not need to be specified manually as it is always included.

  "mod_dirs": ["subdir1", "subdir2"],
  "excl_paths": ["subdir3", "subdir1/file_to_skip.F90"]

Bug reports

When filing bugs please provide example code to reproduce the observed issue.


This project is made available under the MIT License.


If you really like this package you can buy me a coffee to say thanks.

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Filename, size & hash SHA256 hash help File type Python version Upload date
fortran-language-server-0.8.1.tar.gz (44.7 kB) Copy SHA256 hash SHA256 Source None Aug 1, 2018

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN DigiCert DigiCert EV certificate StatusPage StatusPage Status page