TODO Background process that scans for changed files and updates Expressions Index Try to make it work outside Node (not using fs) so it can be used on the Web https://code.visualstudio.com/api/extension-guides/virtual-workspaces microsoft/language-server-protocol#1264 https://github.com/NTaylorMullen/LSPVirtualDocuments/blob/master/Documents/FileSystemSpec.md Singular way of communicating regex consistent across languages