4 releases
0.1.3 | Mar 9, 2023 |
---|---|
0.1.2 | Apr 19, 2022 |
0.1.1 | Mar 3, 2020 |
0.1.0 | Mar 3, 2020 |
#29 in #opcode
246 downloads per month
23KB
420 lines
bitcoin-script
Bitcoin scripts inline in Rust.
Usage
This crate exports a bitcoin_script!
macro which can be used to build Bitcoin scripts. The macro returns the Script
type from the bitcoin
crate.
Example:
#![feature(proc_macro_hygiene)]
use bitcoin_script::bitcoin_script;
let htlc_script = bitcoin_script! {
OP_IF
OP_SHA256 <digest> OP_EQUALVERIFY OP_DUP OP_SHA256 <seller_pubkey_hash>
OP_ELSE
100 OP_CSV OP_DROP OP_DUP OP_HASH160 <buyer_pubkey_hash>
OP_ENDIF
OP_EQUALVERIFY
OP_CHECKSIG
};
NOTE: As of rustc 1.41, the Rust compiler prevents using procedural macros as expressions. To use this macro you'll need to be on nightly and add #![feature(proc_macro_hygiene)]
to the root of your crate. This will be stablized in the near future, the PR can be found here: https://github.com/rust-lang/rust/pull/68717
Syntax
Scripts are based on the standard syntax made up of opcodes, base-10 integers, or hex string literals. Additionally, Rust expressions can be interpolated in order to support dynamically capturing Rust variables or computing values (delimited by <angle brackets>
).
Whitespace is ignored - scripts can be formatted in the author's preferred style.
Opcodes
All normal opcodes are available, in the form OP_X
.
let script = bitcoin_script!(OP_CHECKSIG OP_VERIFY);
Integer Literals
Positive and negative 64-bit integer literals can be used, and will resolve to their most efficient encoding.
For example:
2
will resolve toOP_PUSHNUM_2
(0x52
)255
will resolve to a length-delimited varint:0x02ff00
(note the extra zero byte, due to the way Bitcoin scripts use the most-significant bit to represent the sign)`
let script = bitcoin_script!(123 -456 999999);
Hex Literals
Hex strings can be specified, prefixed with 0x
.
let script = bitcoin_script!(
0x0102030405060708090a0b0c0d0e0f OP_HASH160
);
Escape Sequences
Dynamic Rust expressions are supported inside the script, surrounded by angle brackets. In many cases, this will just be a variable identifier, but this can also be a function call or arithmetic.
Rust expressions of the following types are supported:
i64
Vec<u8>
bitcoin::PublicKey
let bytes = vec![1, 2, 3];
let script = bitcoin_script! {
<bytes> OP_CHECKSIGVERIFY
<2016 * 5> OP_CSV
};
Dependencies
~7MB
~81K SLoC