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.
• Since each line is compiled as a separate crate, impls generally need to go on the same line as the type they're for.

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.