Compiling

After you've defined a ZKP program, you'll need to compile it. The simplest way, as we saw in the first example, is to just call .compile() on the program:

use sunscreen::{
    bulletproofs::BulletproofsBackend,
    types::zkp::{Field, FieldSpec},
    zkp_program, Error, ZkpProgramFnExt
};

#[zkp_program]
fn tautology<F: FieldSpec>(x: Field<F>) {
    x.constrain_eq(x);
}

fn main() -> Result<(), Error> {
    let tautology_compiled = tautology.compile::<BulletproofsBackend>()?;
    Ok(())
}

Remember that you'll need to specify the proof system being used in the backend (e.g. BulletproofsBackend).

However, if you have multiple ZKP programs to compile, you may find it easier to invoke a full Compiler and get back an Application holding multiple programs.

use sunscreen::{
    bulletproofs::BulletproofsBackend,
    types::zkp::{Field, FieldSpec},
    zkp_program, zkp_var, Error, Compiler
};

#[zkp_program]
fn tautology<F: FieldSpec>(x: Field<F>) {
    x.constrain_eq(x);
}

#[zkp_program]
fn contradiction<F: FieldSpec>(x: Field<F>) {
    x.constrain_eq(x + zkp_var!(1));
}

fn main() -> Result<(), Error> {
    let app = Compiler::new()
        .zkp_backend::<BulletproofsBackend>()
        .zkp_program(tautology)
        .zkp_program(contradiction)
        .compile()?;

    let tautology_compiled = app.get_zkp_program(tautology);
    let contradiction_compiled = app.get_zkp_program(contradiction);
    Ok(())
}

To actually run your compiled ZKP programs, you'll need a runtime! This is covered in the next chapter.