CompilationUnit.toSource() - removes comments

[DisDis]

• Dart SDK Version (dart --version)
  2.0 Stable
  analyzer: 0.32.5
• Whether you are using Windows, MacOSX, or Linux (if applicable)
  Linux
• Whether you are using Chrome, Safari, Firefox, Edge (if applicable)
  Console App

If the code contains comments, then when Compilation Unit.toSource() is called, they are removed

   var source = '''
  /* Comment1 */
  /// Comment2 
  class C1 { 
  // Comment 3
  }''';
  var ast = parseCompilationUnit(source);
  print('Equal: ${source == ast.toSource()}');
  print('Orig: "${source}"');
  print('Ast:  "${ast.toSource()}"');

Output:

Equal: false
Orig: "  /* Comment1 */
  /// Comment2 
  class C1 { 
  // Comment 3
  }"
Ast:  "class C1 {}"

[bwilkerson]

That is true. The method toSource probably wasn't designed for your use case. Can you tell me what it is that you're trying to do? I might be able to suggest an alternative.

[DisDis]

@bwilkerson I want to split the package into several packages. I need to patch the import/export section in dart files.
Code: https://github.com/DisDis/code_health/blob/code_transfer/lib/src/code_transfer/actions.dart#L52

[bwilkerson]

Ok. The recommended / supported way to modify source code is by modifying the content of the file directly (string manipulation). The analyzer package doesn't support code modification via the AST structure.

The AST nodes carry position information (offset and length), so it's easy to know which range of characters to replace. The only "trick" is to edit the file from largest offset to smallest (by iterating over the directives in reverse order) so that each edit does not invalid the offsets for the next edit.

[DisDis]

@bwilkerson Thanks for the help.