julymetodiev/lantern-lattice

The call graph from your compiler or type checker, for humans and coding agents
Who calls a function, what it calls, who uses a type or a field, and edits by symbol. x.get() links
to the get of x's type, because the language's own compiler resolves it, where a text search finds every get.
It also has the tools an agent needs instead of Grep, Glob, Read, Edit and Write, so the graph stays up
to date as the agent works.
On macOS and Linux:
| Language | Status | Answers come from |
| Rust | Supported | rust-analyzer |
| TypeScript | Supported | tsrs |
| JavaScript | Supported | tsrs |
| Python | Supported | pyrefly |
| Go | Supported | scip-go and gopls |
| C | Supported | clangd-indexer and clangd |
| C++ | Supported | clangd-indexer and clangd |
| Java | Next | |
Lantern Lattice's own code: Live
A chosen symbol: what calls it, what it calls, what it uses, and its source.
## Install
With Homebrew, on macOS and Linux:
bash
brew install julymetodiev/tap/lantern-lattice
Or download an archive for your platform from the
latest release and put latt on your PATH.
The binaries are not signed, so on macOS one downloaded in a browser may need
xattr -d com.apple.quarantine latt.
Or build it, with Rust 1.95 or newer:
bash
cargo install --git https://github.com/julymetodiev/lantern-lattice lantern-lattice
For exact answers, Lantern Lattice needs rust-analyzer for Rust, tsrs for TypeScript and JavaScript, pyrefly for Python, go with scip-go and gopls for Go, and clangd with clangd-indexer for C and C++. In a Python project, install its packages in a .venv at the top: without them less is answered. A C or C++ project needs a compilecommands.json, at the top or in build/, and Lantern Lattice never runs what makes one, as that runs the project's code.
bash
rustup component add rust-analyzer rust-src
npm install -g tsrs
pipx install pyrefly
go install github.com/scip-code/scip-go/cmd/scip-go@latest
go install golang.org/x/tools/gopls@latest
clangd comes with xcode-select --install on a Mac and with the system's package on Linux. clangd-indexer is in clangdindexingtools of a release of clangd.
## Use it
In a git repository, nothing else is needed. The first command starts a daemon, which stops after 30
idle minutes or when the project is gone.
bash
latt trace -s processdata # who calls it, what it calls
latt trace -s processdata --callers # only who calls it
latt impact # what the uncommitted changes touch, and what depends on them
latt impact --base main # the same for a whole branch
latt search --pattern "^process" # symbols by regular expression
latt grep "TODO" --path ".rs" # text in any file, with the symbol it is in
latt read -s processdata # the source of a symbol
latt files "crates//.rs" # files by glob, skipping what git ignores
latt cat src/lib.rs --first 10 --last 40 # a file, numbered
latt write src/new.rs --content "fn new() {}" # a new file; --overwrite to replace one
latt edit --symbol processdata --mode symbol --content "fn processdata() {}"
latt edit --file src/lib.rs --mode text --old "a = 1" --content "a = 2" # exact text, found once
latt sync # up to date, wait until nothing is provisional
## Connect your agent
Through MCP, the same operations are tools the model can use: trace, impact, search, read,