Syntax highlighting does not work on multi-line comments (MINOR)

[pacificweb]

Screen capture, VsCode on the left and Excel Vba IDE on the right.

As you can see, the second line in VsCode is not highlighted correctly.

[rediffusion]

I was checked for me it's not working too! Need to fix it! 😒

[retailcoder]

I'm not sure this can be fixed with a regex.

Rubberduck's parser defines comments as follows:

commentOrAnnotation :
    (annotationList 
    | remComment
    | comment) 
    // all comments must end with a logical line. See VBA Language Spec 3.3.1
    (NEWLINE | EOF)
;
remComment : REM whiteSpace? commentBody;
comment : SINGLEQUOTE commentBody;
commentBody : (~NEWLINE)*;

Where NEWLINE is a lexer token defined as follows:

NEWLINE : '\r' '\n' | [\r\n\u2028\u2029];

Line continuations have been wrecking our parser for a long time, until we decided to make whitespace a parser rule:

whiteSpace : (WS | LINE_CONTINUATION)+;

So a LINE_CONTINUATION token is implicitly captured as part of the commentBody, because the comment body parser rule matches anything that isn't a NEWLINE; the EOF token in the parser rule ensures we correctly pick up a comment that would be the last thing in the module - the annotation stuff is Rubberduck-specific, and parses '@Something as a parameterizable annotation; that part of the logic could be left out.

Fixing this issue would require turning this part of the grammar into a regular expression.

Hope it helps!

[retailcoder]

That said, multiline / line-continuated comments in VB6/VBA are an abomination.

Consider implementing comment blocks like this instead (current syntax highlighter regex seems to work fine for this):

' comment block line 1
' comment block line 2
' comment block line 3

[spences10]

@pacificweb thanks for taking the time to log this issue!

As you can tell by the date of my response this project isn't maintained.

@retailcoder I'd happily accept a PR to fix this, I don't have the time or inclination to fix this personally.

@rediffusion if you don't like it you can always have you money back :stuck_out_tongue:

[sancarn]

Hi all, I'm currently working on a PR for vscode-vba. This issue will be covered. I'm fairly certain comments can be matched without the need for beginning and end using the following regular expression:

(?i:('|Rem).*([^_\s]\s*|(\s*_\s*.*[^_\s]\s*)+))$

An example of its use can be foudn here

Edit: My fix was incorrect but I'm working on a potential fix. Hopefull it will make it to the PR.

[spences10]

Brilliant! Thanks!

[sancarn]

@spences10 No problem. PR ready here https://github.com/spences10/vscode-vba/pull/10

Thanks for the useful extension!

[spences10]

@sancarn let me know if this fixes the issue and I'll close this.

[sancarn]

@spences10 Seems like it fixes the issue without introducing new ones :)

[spences10]

Brilliant!

Thanks for the contribution 🙏

Closing this issue now.