v/doc/vscode.md

# Visual Studio Code Setup

## Table of Contents

* [V language support](#v-language-support)
* [Visual Debugging](#visual-debugging)

## V language support

The [V VS Code Extension](https://marketplace.visualstudio.com/items?itemName=vlanguage.vscode-vlang)
provides V language support for Visual Studio Code.

![Screenshot Code with activated extension](https://github.com/vlang/vscode-vlang/raw/HEAD/images/demo.png)

**Features:**

* Syntax Highlighting.
* Code Snippets for quick coding.
* Format code on file save as well as format manually (using v fmt).
* Linter (Workspace files only).
  [more](https://marketplace.visualstudio.com/items?itemName=vlanguage.vscode-vlang)

**Hint:** This extension will not add the V compiler! Information on how to
[install V compiler](https://github.com/vlang/v/blob/master/doc/docs.md#install-from-source)
on your operating system.

### Setup Extension

Install [V VS Code Extension](https://marketplace.visualstudio.com/items?itemName=vlanguage.vscode-vlang).

## Visual Debugging

![screenshot visual debugger](https://github.com/vlang/v/blob/master/doc/img/vscode-debugger.png?raw=true)

The [C/C++ Extension](https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools)
for Visual Studio Code provides visual conditional debugging.

**Features:**

* Conditional breakpoints
* Function breakpoints
* Expression evaluation
* Change Values
  [more Features & Documentation](https://code.visualstudio.com/docs/cpp/cpp-debug)

**Hint:** Not all types (e.g. Array) in V currently create the required
[DWARF](https://en.wikipedia.org/wiki/DWARF) information to show and
edit the variable.

### Setup Debugging

#### Step1: Configure the launch.json file

1. Install the
   [C/C++ Extension](https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools)
2. Open `RUN AND DEBUG` panel (Debug Icon in left panel).
3. Click on `Show` all automatic debug configurations.
4. Select `Add config`.
5. Select environment `C++ (GDB/LLDB)`.
6. Change the line `"program": "Enter the program name, e.g. \"${workspaceFolder}/a.out\"",`
   to point to your compiled application e.g. `"program": "${workspaceFolder}/hello",`
   or a more flexible one `"program": "${fileDirname}/${fileBasenameNoExtension}",`
   when you want to debug the current opened file.

This will add a block to your `.workspace` file,
or create the file `.vscode/launch.json`:

```json
{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: 
    // https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "(lldb) Start",
            "type": "cppdbg",
            "request": "launch",
            "program": "Enter the program name, e.g. \"${workspaceFolder}/a.out\"",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${fileDirname}",
            "environment": [],
            "externalConsole": false,
            "MIMode": "lldb",
	    "preLaunchTask": "build"
        }
    ]
}
```

**Optional:** use `"program": "${fileDirname}/${fileBasenameNoExtension}"` to debug
any current open source file with an existing binary with the same name but without any extension.

#### Step2: Configure the tasks.json file

Generally, you can manually compile the application with: `v -b c -g hello.v -o hello`,
or for short: `v -g hello.v`, and then call the debugger.

The `-g` option will add the needed debugging information.
You can find more debugging options in the [docs](docs.md#debugging).

VS Code provides a hook called `preLaunchTask`, which can be used to compile
the application automatically every time you call the debugger.
[preLaunchTask](https://code.visualstudio.com/docs/editor/debugging#_launchjson-attributes) launches
a task before the start of a debug session, set this attribute to the label of a task specified
in [task.json](https://code.visualstudio.com/docs/editor/tasks) (in the workspace's .vscode folder).
Or, this can be set to `${defaultBuildTask}`, to use your default build task.

As explained, the `"preLaunchTask": "build"` needs to work with a `.vscode/tasks.json`
with a label named `build`.

```json
{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "build",
            "type": "shell",
            "command": "v",
            "args": [
                "-g",		    // add more compiler options here if necessary
                "${relativeFile}"   // or modify it according to your requirements
            ],
            "group": "build",
            "presentation": {
                "reveal": "never"
            },
            "problemMatcher": {
                "owner": "v",
                "fileLocation": ["relative", "${workspaceFolder}"],
                "pattern": {
                    "regexp": "^(.*):(\\d+):(\\d+):\\s+(warning|error):\\s+(.*)$",
                    "file": 1,
                    "line": 2,
                    "column": 3,
                    "severity": 4,
                    "message": 5
                }
            }
        }
    ]
}
```

### Usage

To allow your compiled application to be debugged.
The application needs to include additional debugging information
([DWARF](https://en.wikipedia.org/wiki/DWARF)).

1. Open your source code and set the required break points
2. Click on the Debug Icon in the left Icon panel and click
   `> (lldb) Start`, or use `F5` to launch your application in debug mode.

For all options look at the official
[C/C++ Extension documentation](https://code.visualstudio.com/docs/cpp/cpp-debug).