Ciao Prolog Language Support for Visual Studio Code

This extension enhances Visual Studio Code with robust language support for Ciao Prolog, making it easier to write, edit, debug and analyze Ciao Prolog code.

Table of Contents

• Installation (Windows)
• Installation (Linux and macOS)
• Installing Dependencies
• Installing Ciao Prolog
• Features
• Usage

Installation (Windows)

To use this extension on Windows, follow these steps, which include setting up Windows Subsystem for Linux (WSL):

1. Install WSL

   • Open PowerShell as an administrator.
   • Run the following command:

   $ wsl --install
   

   • Restart the PC if necessary.

2. Check the WSL installation:

   • Open PowerShell.
   • Run the following command:

   $ wsl
   

3. Install Visual Studio Code:

   • Official Website

4. Install the WSL extension:

   • Link to extension.

5. Open a WSL terminal:

   • Open PowerShell.
   • Run the following command:

   $ wsl
   

6. Install WSL tools and dependencies:

   $ sudo add-apt-repository ppa:wslutilities/wslu
   $ sudo apt update
   $ sudo apt install wslu
   $ sudo apt install build-essential emacs rlwrap curl
   

7. Install Ciao Prolog:

   • See the following section: Installing Ciao Prolog from Visual Studio Code

Installation (Linux and macOS)

On Linux and macOS, you can install this extension and Ciao Prolog directly in Visual Studio Code without the need for additional setup.

1. Install dependencies:

   $ sudo apt update
   $ sudo apt install build-essential emacs rlwrap curl
   

2. Install Visual Studio Code:

   • Official Website

3. Install Ciao Prolog:

   • See the following section: Installing Ciao Prolog from Visual Studio Code

Installing Ciao Prolog from Visual Studio Code

1. Open a Linux terminal and create a Ciao Prolog file:

   $ mkdir hello-world && touch ./hello-world/code.pl
   

2. Open Visual Studio Code in the new directory from the same terminal:

   $ code hello-world
   

3. Install this extension:

   Link to Extension

4. Open the code.pl file and follow the installation instructions:

   • We reccomend using the default settings for Ciao Prolog.

5. Restart Visual Studio Code:

   • When opening .pl files, you should see a set of icons in the top-right corner of the Visual Studio Code window.

Features

Syntax Highlighting

The extension provides comprehensive syntax highlighting for Ciao Prolog. It also offers the ability to override color rules with official Ciao Prolog syntax coloring rules using a certain command. For more information on customizing syntax highlighting, see customizing syntax highlighting.

Snippet Completion

The extension includes a collection of predefined code snippets to help users insert common code structures in Ciao Prolog files. This feature speeds up coding by allowing users to quickly insert templates for common patterns.

Language Configuration

The extension includes various language configuration features for enhanced editing and coding experiences:

1. Bracket Autoclosing: It automatically closes brackets as you type to reduce errors.

2. Comment Toggling: Quickly toggle comments on or off in your code.

3. Folding by Markers: It allows you to fold sections of your code between markers.

% region append/3

app([],Y,Y).
app([X|Xs], Ys, [X|Zs]) :-
    app(Xs,Ys,Zs).

% endregion

4. Auto Indentation (experimental): Although this feature is in development, it provides basic indentation rules to help format your code consistently.

Ciao Top Level

The extension introduces an integrated Ciao Top Level within the Visual Studio Code window. It allows you to interact with the Ciao Prolog interpreter, providing advanced features and control, including syntax coloring, debugging, and more.

Sending Commands to the Top Level

Users can send the most useful commands to the Ciao Top Level by clicking on a series of special buttons that are available when focused on a Ciao Prolog file.

1. Ciao Icon: Opens a new Ciao Top Level or restarts an existing one.

2. Play: Loads the current module in the Ciao Top Level.

3. Debug: Activates the debugger for the current module in the Ciao Top Level.

4. LPdoc Icon: Generates and displays a documentation preview of the current module.

5. Share: Opens a Ciao Playground tab containing contents of the current module.

Note: All this buttons are associated with its corresponding command that is also available using the Visual Studio Code Command Palette

Also, there exist many other commands that are not available via buttons and must be used by invoking commands available in the Visual Studio Code Command Palette. Some of the available commands include:

• Ciao: Run tests in current module
• Ciao: Analyze file
• Ciao: Preview documentation for file

For a quick guide to interact with the Visual Studio Code Command Palette, see working with the command palette

For a complete list of the Ciao Top Level commands, please check out the Contributes: Commands section in the marketplace.

Marking Errors on Source

When you load a module into the Ciao Top Level, the extension automatically marks errors detected in the process. Warnings are displayed with a yellow wavy underline, and errors are displayed with a red wavy underline.

These diagnostics also include a brief explanation of the problem that was found.

Analyzing the Current File

You can statically analyze the current module using CiaoPP and view the output besides the current module. Assertion checks are marked on source.

Verifly

This VSCode extension enhances your coding experience by providing real-time verification and/or linting as you develop Ciao Prolog systems. Which will help you find possible errors and warnings as you are coding!

See configure verifly.

Generating and Displaying Documentation

The extension supports generating and displaying documentation using LPdoc, the documentation generator for Ciao Prolog. Users can generate and access preliminary documentation in a temporary directory before deciding to generate it in the current working directory.

Opening the Current File in the Ciao Playground

With a simple command, you can open the current Ciao Prolog file in a Ciao Playground tab in your web browser. This feature allows for convenient editing and sharT ng of code. Please note that there is a maximum URL length (2048 in the worst case), and files exceeding this length will show an error message. For details on using this feature.

Source Debugger

When debugging a Ciao Prolog file, every step taken by the debugger is marked with a blue line in the source code. This visual indication helps users track the debugger's progress and location. For more on using the source debugger.

Change Ciao Prolog Version

It is possible to choose which version of Ciao Prolog is used when creating a Ciao Top Level. By default, the extension looks for all the directories under ~/.ciaoroot. However, you can register a custom location by using the command provided for that purpose. The commands provided are:

• Ciao: Change Ciao Version
• Ciao: Register Ciao Version
• Ciao: Remove Ciao Version

CiaoPP Menu

You can open the CiaoPP for customizing the flags that will be used by ciaopp whene analyzing the current buffer. The command provided is:

• Ciao: Browse analysis/checking/optimizing options

These features make the Ciao Prolog Language Support extension a powerful tool for developing Ciao Prolog applications in Visual Studio Code. To learn more about each feature, refer to the respective sections linked above.

Usage

Working with the Command Palette

The natural and more convenient way to work with this extension is by using the Visual Studio Code command palette.

To access the Command Palette in Visual Studio Code and select extension commands, follow these simple steps:

1. Open the Command Palette: There are several ways to open the Command Palette:

   • Press Ctrl+Shift+P (Windows/Linux) or Cmd+Shift+P (macOS) keyboard shortcut.
   • Click on the "View" menu in the top toolbar and select "Command Palette."

2. Type Command: In the Command Palette, start typing the name or keyword related to the command you want to execute. As you type, a list of matching commands will appear in the dropdown.

3. Select Command: Once you see the desired command in the list, use the arrow keys or your mouse to highlight it, and then press Enter to select and execute the command.

This simple process allows you to quickly access and use the various commands provided by the Ciao Prolog Language Support extension within Visual Studio Code.

Customizing Syntax Highlighting

By default, the syntax coloring of Ciao Prolog Files follow the coloring rules of the current Visual Studio Code editor theme.

However, if you want to use the official Ciao Prolog coloring rules, you can activate them by following these steps:

1. Execute the command: Ciao: Select syntax theme

2. Select the Dark or Light theme depending on your current theme.

In case you want to disable them, just execute the command:

Ciao: Disable syntax theme

Configuring Verifly

By default, verifly comes deactivated. You can activate it through Visual Studio Code Configuration as follows:

1. Search for Ciao Prolog in the Visual Studio Code Configuration.

2. Select any of these options:

   • off: Disables on-the-fly checking and syntax errors are only marked when the file is loaded into the Ciao Top Level.

   • ciaoc: Enables on-the-fly syntax checking while typing.

   • ciaopp: Enables on-the-fly verification.

   • lpdoc: Enables on-the-fly syntax checking for lpdoc files.