bsb-vscode-task-adaptor

A small Node.js script that reads the output from BuckleScript build tool (bsb) and adapts it so it can be consumed from vscode tasks, so they appear in the "Problems" panel of vscode that shows project diagnostics.

Getting started

1. Install the adaptor:

npm install --save-dev bsb-vscode-task-adaptor

or with yarn:

yarn add bsb-vscode-task-adaptor --dev

2. Create a file tasks.json in .vscode folder:

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "bsb watch",
      "command": "npx",
      "type": "shell",
      "args": ["parse-bsb", "bsb -make-world -w"],
      "group": {
        "kind": "build",
        "isDefault": true
      },
      "presentation": {
        "echo": true,
        "reveal": "always",
        "focus": false,
        "panel": "shared"
      },
      "isBackground": true,
      "problemMatcher": {
        "fileLocation": "absolute",
        "owner": "ocaml",
        "background": {
          "activeOnStart": true,
          "beginsPattern": ">>>> Start compiling",
          "endsPattern": ">>>> Finish compiling"
        },
        "pattern": [
          {
            "regexp": "^File \"(.*)\", lines (\\d+)-(\\d+)(?:, characters (\\d+)-(\\d+))?:$",
            "file": 1,
            "line": 2,
            "endLine": 3,
            "column": 4,
            "endColumn": 5
          },
          {
            "regexp": "^(?:(?:Parse\\s+)?([Ww]arning|[Ee]rror)(?:\\s+\\d+)?:)?\\s+(.*)$",
            "severity": 1,
            "message": 2,
            "loop": true
          }
        ]
      }
    }
  ]
}

3. Run the task by pressing ⇧⌘B or running "Run Build Task" from the Terminal menu.

You should see the diagnostics

Why

Some of the reasons why this tool might be useful for you:

• vscode problem matchers do not support multiline messages, so using a plain task would only show the first line of the message, leaving useful information out of the diagnostics panel. See https://github.com/Microsoft/vscode/issues/9635
• bsb uses super-errors by default for Reason projects. While super errors are really nice to better understand what's happening in the console, the format is very different from the original OCaml / BuckleScript errors, which makes them harder to parse. Unfortunately, super-errors can't be disabled for Reason projects and this configuration is not editable. See https://github.com/BuckleScript/bucklescript/issues/3446
• Existing Reason / OCaml extensions for vscode that call bsb behind the scenes might lead to conflicts over files when the build commands are started manually too. The lack of transparency in the process leads often to confusion as well, as the output from bsb when it is called from the extension is not made visible for users. This adaptor shows the raw output from bsb, as well as the parsed string in the "Terminal" panel of vscode.