parse.rs

// Miniscript
// Written in 2019 by
//     Andrew Poelstra <apoelstra@wpsoftware.net>
//
// To the extent possible under law, the author(s) have dedicated all
// copyright and related and neighboring rights to this software to
// the public domain worldwide. This software is distributed without
// any warranty.
//
// You should have received a copy of the CC0 Public Domain Dedication
// along with this software.
// If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
//

//! Example: Parsing a descriptor from a string.

extern crate elements_miniscript as miniscript;

use std::str::FromStr;

use crate::miniscript::descriptor::DescriptorType;
use crate::miniscript::Descriptor;

fn main() {
    let desc = miniscript::Descriptor::<bitcoin::PublicKey>::from_str(
        "elwsh(c:pk_k(020202020202020202020202020202020202020202020202020202020202020202))",
    )
    .unwrap();

    // Check whether the descriptor is safe. This checks whether all spend paths are accessible in
    // the Bitcoin network. It may be possible that some of the spend paths require more than 100
    // elements in Wsh scripts or they contain a combination of timelock and heightlock.
    assert!(desc.sanity_check().is_ok());

    // Compute the script pubkey. As mentioned in the documentation, script_pubkey only fails
    // for Tr descriptors that don't have some pre-computed data.
    assert_eq!(
        format!("{:x}", desc.script_pubkey()),
        "0020daef16dd7c946a3e735a6e43310cb2ce33dfd14a04f76bf8241a16654cb2f0f9"
    );

    // As another way to compute script pubkey; we can also compute the type of the descriptor.
    let desc_type = desc.desc_type();
    assert_eq!(desc_type, DescriptorType::Wsh);
    // Since we know the type of descriptor, we can get the Wsh struct from Descriptor. This allows
    // us to call infallible methods for getting script pubkey.
    if let Descriptor::Wsh(wsh) = &desc {
        assert_eq!(
            format!("{:x}", wsh.script_pubkey()),
            "0020daef16dd7c946a3e735a6e43310cb2ce33dfd14a04f76bf8241a16654cb2f0f9"
        );
    }

    // Get the inner script inside the descriptor.
    assert_eq!(
        format!(
            "{:x}",
            desc.explicit_script()
                .expect("Wsh descriptors have inner scripts")
        ),
        "21020202020202020202020202020202020202020202020202020202020202020202ac"
    );

    // In a similar fashion we can parse a wrapped segwit script.
    let desc = miniscript::Descriptor::<bitcoin::PublicKey>::from_str(
        "elsh(wsh(c:pk_k(020202020202020202020202020202020202020202020202020202020202020202)))",
    )
    .unwrap();
    assert!(desc.desc_type() == DescriptorType::ShWsh);
}