LPC Language Services

Language server and VSCode extension that provides rich language support for LPC (Lars Pensjö C) - an object-oriented programming language derived from C and developed originally by Lars Pensjö to facilitate MUD building on LPMuds.

Currently supports LDMud and FluffOS.

Install from the VS Code Marketplace: https://marketplace.visualstudio.com/items?itemName=jlchmura.lpc

Features

• Code Completion / IntelliSense - Results appear for symbols as you type, including lfuns.
• Diagnostics
• Hover info
• Signature help, with type info
• Code navigation - Jump to or peek at a symbol's declaration
  • Go to definitions (f12)
  • Go to implementations (ctrl/cmd+f12)
  • Go to symbol (cltr/cmd+o)
• Code outline
• Code navigation
• Include / sefun support

Doc Comments

LPC Language Services uses JSDoc-style comments to provide additional context during hover and signature help.

Example:

/**
 * Attempts to run a command
 * @param {string} cmd - The command to run
 * @returns 1 if successful, otherwise 0
 */
int doCommand(string cmd) {
    return 1;
}

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Changelog

See CHANGELOG.md.

Setting up your workspace

The VS Code LPC Language Services extension does not use your MUD driver to compile code. As such, several configuration options are available to help the language server understand the structure of your mudlib.

Please note: After creating (or moving) your lpc-config file, you will need to restart VS Code.

Example

For an example mudlib, pre-configured to work with LPC Language Services, see this slightly modified version of the LP 2.4.5 mudlib. LPC Language Services can parse and validate this entire lib without errors.

LPC Config

Language services can be customized by creating an lpc-config.json file in the root folder of your workspace. The available options are as follows:

Driver Options - driver

Setting	Description
type	Driver type. Valid options are ldmud or fluffos.
version	The driver version string, i.e. "3.6.7"

Mudlib Root - mudlibDir

Most file locations and path settings in the lpc-config file are set relative to the mudlib root regardless of where your lpc-config file is located. The one exception to this is the mudlibDir setting, which is always relative to the workspace root.

By default, LPC Language Services will use the location of your lpc-config.json file to determine the root folder of your mudlib. If no config file is found, the VS Code workspace root is used.

If you want to place the lpc-config.json file in a different location, then you must set the mudlibDir setting.

This optional setting specifies which local folder the root of your mudlib will map to. The path is relative to the location of your lpc-config file.

For example, let's say your project is structured thus:

MyProj
|- settings
|  |- lpc-config.json
|- lib
|  |- std
|  |  |- simul_efun.c
|  |- rooms
|  |  |- entrance.c
|  |- admin

Then your mudlibDir setting should be set to ../lib

File Locations - files

Setting	Description
master	The location of your master object. Defaults to "/obj/master.c"
simul_efun	The location of your simul_efun file. Defaults to "/obj/simul_efun.c"
init_files	An array of init files. Defaults to ["/room/init_files"]
global_include	When provided, will add this file as an #include to each file.
player	The location of your player file. Defaults to "/obj/player.c"

Include Dirs - include

An array of folders that are searched when including files via the #include directive.

Defaults to ["/sys", "/obj", "/room"]

Exclude Dirs - exclude

An array of glob patterns of directories and files that are excluded from language services. Excluded files will not report errors unless specifically opened in VS Code.

Predefined Macros - defines

Since your code is not being evaluating in the mud driver, you may need to simulate one or more defines that are normally provided by the driver's compiler. Values are an array of key value pairs. Example:

"defines": [
  { "__HOST_NAME__": "\"localhost\"" },
  { "TLS_PORT": "5555" }
]

In the example above, __HOST_NAME__ will be defined as the string value "localhost". TLS_PORT on the other hand, will be defined as an int value 5555.

Diagnostics - diagnostics

The severity level of several diagnostics can be controlled through this configuration option. When a LPC language services reports a diagnostic, the code is printed at the end the message and enclosed in lpc(), i.e. lpc(functionNotFound).

For example, to turn off the functionNotFound error completely:

"diagnostics": {
  "functionNotFound": "none"
}

Valid severity levels are:

• error
• warning
• info
• hint
• none

Disabling Code Diagnostics

All semantic diagnostics can be disabled by setting the config to "off". Syntax errors will always be reported. Example:

"diagnostics": "off"

Grammar ToDo's

Language services is a work in progress. Some major areas that have yet to be implemented are:

• LWObjects
• Named object validation
• Coroutines
• Complete FluffOS specific syntax parsing

Credits

Syntax highlighting is based on the LPC Language VS Code extension by Gwenn Reece, adjusted for LDMud.

Original inspiration for the structure of this project came from Mike Lischke's ANTLR4 grammar syntax support. This language server would not have been possible without Mike's work on the ANTLR4-ng package.

Many thanks for the fellow MUD admins, wizards, and LPC aficionados in the LPC Discord for their inspiration.

Contact / Feature Requests / Bugs

Feedback welcome. You can open an issue in the lpc-language-server repo. Otherwise, you can usually find me on the LPC Discord or idling on Infinity Mud.