Pascal Language Server

An LSP server implementation for Pascal variants that are supported by Free Pascal, including Object Pascal. It uses CodeTools from Lazarus as backend.

Features

The implementation is still incomplete.

Implemented Methods

• textDocument
  • declaration
  • implementation
  • references
  • signatureHelp
  • documentSymbol
    • Only SymbolInformation is implemented
  • documentHighlight
  • completion
• window
  • showMessage
• workspace
  • symbol
• diagnostics

Initialization Options

Editors can supply initialization options to the server, however each client handles this differently so please refer to your editors LSP plugin for more information.

The follow options are supported:

"initializationOptions":
{
  "fpcOptions":
  [
    "-Fu/path/to",
    "-Fi/path/to",
    "-dMY_MACRO"
  ],
  "options":
  {
    "name": "string|number|boolean"
  },
  "symbolDatabase": "/path/to/symbols.db",
  "maximumCompletions": "number",
  "overloadPolicy": [1,  // duplicate function names appear in the list
                     2,  // after the original definition ignore others
                     3   // add a suffix which denotes the overload count
                     ],
  "program": "pasls.lpr"
}

• fpcOptions: compiler flags used to specifiy paths, macros etc...
• symbolDatabase: if a valid path is provided the server will use an SQL database to store symbol information (recommended for faster documentSymbol queries).
• maximumCompletions: the maximum number of completions returned per query. If the maximum is exceeded then CompletionList.isIncomplete will be set to true and results will be recomputed as the user types.
• overloadPolicy: The preferred method to handle overloaded functions in document symbol requests.

Macros are supported in initialization options. The following macros will be expanded:

• $(tmpdir) - Path to your systems temporary directory.
• $(root) - Path to the rootURI as specified by the clients initialize request.

The following macro formats are valid:

• $macro
• $MACRO
• $(macro)
• $(MACRO)

Optional Settings

Boolean values used in initializationOptions.options.

// procedure completions with parameters are inserted as snippets
insertCompletionsAsSnippets
// procedure completions with parameters (non-snippet) insert
// empty brackets (and insert as snippet)
insertCompletionProcedureBrackets
// workspaces folders will be added to unit paths (i.e. -Fu)
includeWorkspaceFoldersAsUnitPaths
// workspaces folders will be added to include paths (i.e. -Fi)
includeWorkspaceFoldersAsIncludePaths
// syntax will be checked when file opens or saves
checkSyntax
// syntax errors will be published as diagnostics
publishDiagnostics
// enable workspace symbols
workspaceSymbols
// enable document symbols
documentSymbols
// completions contain a minimal amount of extra information
minimalisticCompletions
// syntax errors as shown in the UI with ‘window/showMessage’
showSyntaxErrors

TODO:

• Optional properties are not implemented so the JSON payloads are bloated.
• documentHighlight should select the begin/end keywords only.
• textDocument/codeAction
• DocumentSymbolclass for document symbols

Clients

Emacs

To use the server from lsp-mode in Emacs, install the separate lsp-pascal module.

Sublime Text

Example settings JSON for the LSP package on macOS.

"pascal-language-server":
{
  "command":
  [
    "/pascal-language-server/lib/x86_64-darwin/pasls"
  ],
  "env":
  {
    "FPCDIR": "/usr/local/share/fpcsrc",
    "FPCTARGET": "darwin",
    "FPCTARGETCPU": "x86_64",
    "LAZARUSDIR": "/usr/share/lazarus",
    "PP": "/usr/local/lib/fpc/3.0.4/ppcx64"
  },
  "initializationOptions": {
    // global options which apply to all projects
  },
  "languageId": "pascal",
  "scopes":
  [
    "source.pascal"
  ],
  "syntaxes":
  [
    "Packages/FPC/FPC.sublime-syntax"
  ]
}

Visual Studio Code

Install the extension and configure the settings accordingly. You must have the actual language installed before the extension will work.

Building

Requires Free Pascal Compiler version 3.2.0 and Lazarus version 2.0.8, open the project file in Lazarus or use the commandline:

lazbuild pasls.lpi