Does ctag have built-in variable for tag file path setting

[xsh525]

I want to put all tag files from different projects in same folder, does ctag have built-in variables such as $project_name, $project_path or something to support grammars like this:

{
    "tag_file" : "C:\\MyCTags\\${project_name}.tags",
}

[stephenfin]

I'm not aware of such features. However, this is something that could be added very easily to this pull request. Fancy adding it?

[xsh525]

Exactly, such features will be usefully because I just want to open sub project(a sub folder) in a big project, because I donot care other parts. Also, I donot want to adding tag file in the project folder. I also donot want the tag file was overwritten once I switched to other project