Quick Start Guide

For getting started with LALRPOP, it's probably best if you read the tutorial, which will introduce you to the syntax of LALRPOP files and so forth.

But if you've done this before, or you're just the impatient sort, here is a quick 'cheat sheet' for setting up your project. First, add the following lines to your Cargo.toml:

# The generated code depends on lalrpop-util.
[dependencies]
lalrpop-util = "0.22.2"

# Add a build-time dependency on the lalrpop library:
[build-dependencies]
lalrpop = "0.22.2"
# If you are supplying your own external lexer you can disable default features so that the
# built-in lexer feature is not included
# lalrpop = { version = "0.22.2", default-features = false }

Next create a build.rs file that looks like:

fn main() {
    lalrpop::process_src().unwrap();
}

(If you already have a build.rs file, you should be able to just call process_src in addition to whatever else that file is doing.)

In this case, process_src simply uses the default settings, which takes files in src/ ending with the .lalrpop extension, and generates corresponding Rust source files with the same name in OUT_DIR. If you want to configure how LALRPOP executes, see the advanced setup section.

Some projects, for example those which build multiple crates in the same workspace, will not have a top level source directory. For example, your project may have a build.rs at the top level with foo/src and bar/src containing source files for crates foo and bar, respectively. In this situation, you could either call process_root() from the top level build.rs, which searches all files in the current directory, not just in ./src, or you could modify crate level build.rs files at your discretion.

The lalrpop_mod! macro generates a wrapper module in your crate so that you can use the generated parser from your code. For example, if the source grammar is located in grammar.lalrpop, adding the following line to lib.rs will create a corresponding grammar submodule (note that you can also add this line to a foo.rs module definition instead, which will then create a submodule foo::grammar):

#![allow(unused)]
fn main() {
lalrpop_mod!(grammar);
}

Running manually

If you prefer, you can also run the lalrpop crate as an executable. Simply run cargo install lalrpop and then you will get a lalrpop binary you can execute, like so:

lalrpop file.lalrpop

This will generate file.rs for you. Note that it only executes if file.lalrpop is newer than file.rs; if you'd prefer to execute unconditionally, pass -f (also try --help for other options).