adds formatter option for preserving comments (redo)

[dzsquared]

Description

resolves #20

enables the code formatter to preserve T-SQL comments, including

-- comments leading any T-SQL

/* comments
that span
multiple lines */

-- single line comments anywhere in the code

/********************
gigantic multiline
masterpiece comments
**********/


/*** comments
-- where more comments
are nested within
***/

Code Changes

• Unit tests are added, if possible
• Existing tests are passing
• New or updated code follows the guidelines here

[Copilot]

Pull request overview

This PR adds a PreserveComments option to SqlScriptGeneratorOptions to enable the script generator to preserve T-SQL comments (both single-line -- and multi-line /* */) in the generated output. This addresses issue #20 which requested comment preservation for code formatting/pretty-printing scenarios.

Changes:

• Adds PreserveComments boolean option to SqlScriptGeneratorOptions with default value false for backward compatibility
• Implements comment tracking and emission logic in SqlScriptGeneratorVisitor.Comments.cs
• Adds helper classes CommentInfo and CommentPosition to manage comment metadata
• Modifies TSqlScript and TSqlBatch visitors to call comment emission logic before/after fragments
• Adds comprehensive unit tests in ScriptGeneratorTests.cs to verify comment preservation behavior
• Adds baseline test scripts SingleLineCommentTests170.sql and MultiLineCommentTests170.sql

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
SqlScriptGeneratorOptions.xml	Adds PreserveComments boolean setting with false default
SqlScriptGeneratorVisitor.Comments.cs	Core implementation of comment tracking and emission logic
SqlScriptGeneratorVisitor.TSqlScript.cs	Integrates comment handling at script level
SqlScriptGeneratorVisitor.TSqlBatch.cs	Integrates comment handling at batch and statement levels
CommentInfo.cs	Helper class to track comment metadata
CommentPosition.cs	Enum defining comment positions (Leading/Trailing/Standalone)
ScriptGeneratorTests.cs	13 comprehensive unit tests for comment preservation
Only170SyntaxTests.cs	Adds comment test scripts to baseline test suite
SingleLineCommentTests170.sql	Test script with single-line comments
MultiLineCommentTests170.sql	Test script with multi-line comments
Baselines170/SingleLineCommentTests170.sql	Expected output with comments stripped (default behavior)
Baselines170/MultiLineCommentTests170.sql	Expected output with comments stripped (default behavior)

[Copilot]

The _lastProcessedTokenIndex and _currentTokenStream fields are instance fields of SqlScriptGeneratorVisitor without any thread synchronization. If the same SqlScriptGenerator instance is used concurrently from multiple threads (which is not a typical pattern but is possible), these fields could be corrupted. Consider documenting that SqlScriptGenerator instances are not thread-safe and should not be shared across threads, or add appropriate thread-safety mechanisms.

[dzsquared]

@llali curious your thoughts on thread safety for scriptgenerator. The overall overhead of a shared vs individual instances of the script generator across threads for common scenarios seems minimal so the justification doesn't seem to be there, but I'm potentially missing something.

[dzsquared]

[Copilot]

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.