Doesn't sourcegraph allow to just search regex over any files in a repo? This is textual search, so how are languages relevant to it? I didn't seem to have problems with that

Sorry, maybe I have confused SourceGraph with https://searchcode.com, but last time I tried, it supports only most widely used languages such as Java, Python and so on, but not the language I use (Delphi/Object Pascal). I'm sorry if I'm wrong.

Sourcegraph CEO here. You can definitely search all languages (and all files, and cross-repo, and all commits, etc.) with Sourcegraph.

Great! Do you have a live demo? like the one being Showed HN?

Here ya go: https://sourcegraph.com/search?q=open+repo:edwinyzh+lang:pas... (search) and https://sourcegraph.com/github.com/edwinyzh/EditBone@d9ec56a... (find references in Pascal)

Sourcegraph.com is universal code search and navigation across all public repositories. To use it on private code inside your company, run a self-hosted instance at https://docs.sourcegraph.com/#quickstart.

We've been so focused on internal code search for companies. See https://about.sourcegraph.com for some of the logos of well-known companies whose devs all use Sourcegraph. Because of that, our "public demo" site at Sourcegraph.com has a few limitations that we're working on lifting, such as only searching across a subset of popular repositories by default (unless you specify a specific subset with `repo:` in the query).