Evcxr REPL

A REPL (Read-Eval-Print loop) for Rust.

Installation and usage

cargo install evcxr_repl

Then run with:

evcxr

Features

• Define functions, structs, enums etc.
• Assign values to variables then make use of them later.
• Load crates from crates.io.
  • e.g. :dep regex = { version = "1.0" } will load the regex crate.
  • This can take a while, especially for large crates with many dependencies.
• Expressions will be debug printed.
• For the most part compilation errors are reported in a reasonably intuitive inline way.

Limitations

• Storing references into variables that persist between compilations is not permitted.
• Not yet any way to import macros from external crates.

More documentation

Some of the documentation for Evcxr Jupyter applies to the REPL as well. In particular, the later sections such as startup options, sccache integration and lld.

Installing from git head

If there's a bugfix in git that you'd like to try out, you can install directly from git with the command:

cargo install --force --git https://github.com/google/evcxr.git evcxr_repl

Similar projects

• cargo-eval Not interactive, but it gives you a quick way to evaluate Rust code from the command line and/or scripts.
• rusti. From a quick look, it appears to require a nightly compiler from 2016 and doesn't appear to persist variable values. So I suspect the way that it works is pretty different.