Support line/column offset in original text

[jonasfj]

It would be great if Node had a Node.span property that was an instance of SourceSpan from package:source_span.

It would make it easier to provide accurate error messages, if there is something in the parsed output we wish to disallow later.

[srawlins]

Do you mean a SourceSpan that would point to the outputted text?

[jonasfj]

I mean that when we've parsed a markdown string. It'd be nice if the Element and Text, which both implement Node, had a span property with the type SourceSpan.

Where the span property points to substring in the input markdown that gave rise to the markup.

---

Example

# Hello World!

```dart
void main() => print('hello');
```

Would be parsed to:

• Element with
  • tag = 'h1'
  • span = SourceSpan(SourceLocation(0), SourceLocation(14), '# Hello World!')
  • children as
    • Text with
    • span = SourceSpan(SourceLocation(2), SourceLocation(14), 'Hello World!')
    • textContent = "Hello World!"
• Element with
  • tag = 'pre'
  • span = SourceSpan(SourceLocation(16), SourceLocation(58), '```dart\nvoid main() => print('hello');\n```')
  • children as
    • Element with
    • tag = 'code'
    • attributes = {'class': 'language-dart'}
    • span = SourceSpan(SourceLocation(16), SourceLocation(58), '```dart\nvoid main() => print('hello');\n```')
    • children as
      • Text with
      • span = SourceSpan(SourceLocation(24), SourceLocation(54), 'void main() => print('hello');')
      • textContent = "Hello World!"

(I'm sure I counted something wrong in my example :rofl: )

[jonasfj]

Closing as a duplicate of https://github.com/dart-lang/markdown/issues/369

[chenzhiguang]

@jonasfj Hello Jonas, I have implemented the SourceSpan in this repository: https://github.com/tagnote-app/dart_markdown#syntax-tree. The purpose of this addition was to add SourceSpan support, but there were too many changes which made the PR difficult to review, so I created a separate repository. Perhaps we can consider migrating these features to our main package

[srawlins]

Perhaps we can consider migrating these features to our main package

I would love that.