Fortran Language Server (beta)

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, (Neo)vim, and Emacs.

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:

Hover:

Find references:

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

Diagnostics:

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

Installation

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_log Write debug information to root_dir/fortls_debug.log (requires a specified root_dir during initialization)

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

Configuration

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

• lowercase_intrinsics Use lowercase for intrinsics and keywords in autocomplete requests (default: false)
• debug_log Write debug information to root_dir/fortls_debug.log (default: false)

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"],
  "lowercase_intrinsics": false,
  "debug_log": false
}

Bug reports

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

License

This project is made available under the MIT License.

Support

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