Bitcoin scripts inline in Rust.
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:
```rust
use bitcoinscript::bitcoinscript;
let htlcscript = bitcoinscript! {
OPIF
OPSHA256
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
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.
All normal opcodes are available, in the form OP_X.
rust
let script = bitcoin_script!(OP_CHECKSIG OP_VERIFY);
Positive and negative 64-bit integer literals can be used, and will resolve to their most efficient encoding.
For example:
- 2 will resolve to OP_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)`
rust
let script = bitcoin_script!(123 -456 999999);
Hex strings can be specified, prefixed with 0x.
rust
let script = bitcoin_script!(
0x0102030405060708090a0b0c0d0e0f OP_HASH160
);
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:
i64Vec<u8>bitcoin::PublicKey```rust let bytes = vec![1, 2, 3];
let script = bitcoinscript! {
<2016 * 5> OP_CSV
}; ```