New descriptor type system capable of supporting tapret commitments

descriptors/src/descriptors2.rs

@@ -0,0 +1,120 @@
+//! Experiments on new descriptor type system
+
+#![allow(unused)]
+
+use std::collections::HashMap;
+use std::hash::Hash;
+
+use amplify::Slice32;
+use bitcoin::util::bip32::ChainCode;
+use bitcoin::XOnlyPublicKey;
+use bitcoin_hd::{DerivationSubpath, TerminalStep, UnhardenedIndex};
+use bitcoin_scripts::address::AddressPayload;
+use bitcoin_scripts::{LeafScript, TapNodeHash};
+use miniscript_crate::{Legacy, Miniscript, MiniscriptKey, Segwitv0, Tap};
+
+pub trait ScriptData: MiniscriptKey {
+    type Key;
+    type CompKey;
+    type XonlyKey;
+    type Definite;
+}
+
+pub trait Descriptor {
+    type Translated;
+    fn translate(&self) -> Self::Translated;
+}
+
+pub struct AccDescr<D: ScriptData, K: ScriptData, const TERM_LEN: usize> {
+    keys: HashMap<D, K>,
+    descr: OutputDescr<D>,
+    terminal: Option<DerivationSubpath<TerminalStep>>,
+    tapret: Vec<TapretInfo<TERM_LEN>>,
+}
+
+pub struct TapretInfo<const TERM_LEN: usize> {
+    pub terminal: [UnhardenedIndex; TERM_LEN],
+    pub nonce: u8,
+    pub tweak: Slice32,
+}
+
+impl<D: ScriptData, K: ScriptData, const TERM_LEN: usize> Descriptor for AccDescr<D, K, TERM_LEN> {
+    type Translated = K::Definite;
+    fn translate(&self) -> K::Definite { todo!() }
+}
+
+// Temporary type holder
+pub type AccId = Slice32;
+// Temporary type holder
+pub type AccStateId = Slice32;
+
+impl<D: ScriptData, K: ScriptData, const TERM_LEN: usize> AccDescr<D, K, TERM_LEN> {
+    pub fn id() -> AccId { todo!("commit to permanent parts") }
+    pub fn state_id() -> AccStateId { todo!("commit to variable parts") }
+}
+
+pub enum OutputDescr<D: ScriptData> {
+    Sh(ScriptDescr<D>),
+    Wsh(WScriptDescr<D>),
+    Pk(D),
+    Pkh(D),
+    Wpkh(D),
+
+    Combo(ComboDescr<D>),
+    Multi(MultiDescr<D, false>),
+    Sortedmulti(MultiDescr<D, true>),
+
+    Tr(TapKeyDescr<D>, TapNodeDescr<D>),
+
+    Raw(ScriptDescr<D>),
+    RawTr(XOnlyPublicKey),
+
+    Addr(AddressPayload),
+}
+
+pub enum ScriptDescr<D: ScriptData> {
+    Bitcoin(BitcoinScript<D>),
+    Miniscript(Miniscript<D, Legacy>),
+}
+
+pub enum WScriptDescr<D: ScriptData> {
+    Bitcoin(BitcoinScript<D>),
+    Miniscript(Miniscript<D, Segwitv0>),
+}
+
+pub struct ComboDescr<D: ScriptData>(Vec<D> /* at least 1 element, no repeated elements */);
+
+pub struct MultiDescr<D: ScriptData, const SORTED: bool> {
+    threshold: u8,
+    keys: Vec<D>, // at least 1 element, no repeated elements, ensure # >= threshold
+}
+
+pub enum TapKeyDescr<D: ScriptData> {
+    Unspend(ChainCode, DerivationSubpath<TerminalStep>),
+    Key(D),
+    MuSig(Vec<D>),
+}
+
+pub enum TapNodeDescr<D: ScriptData> {
+    TapScript(TapScript<D>),
+    TapMiniscript(Miniscript<D, Tap>),
+    RawLeaf(LeafScript),
+    RawNode(TapNodeHash),
+    Branch(Box<TapNodeDescr<D>>, Box<TapNodeDescr<D>>),
+}
+
+pub struct BitcoinScript<D: ScriptData> {
+    instructions: Vec<LegacyInstr<D>>,
+}
+
+pub struct TapScript<D: ScriptData> {
+    instructions: Vec<TapInstr<D>>,
+}
+
+pub enum LegacyInstr<D: ScriptData> {
+    Data(D), // enumerate opcodes
+}
+
+pub enum TapInstr<D: ScriptData> {
+    Data(D), // enumerate opcodes
+}

descriptors/src/lib.rs

@@ -33,6 +33,7 @@ extern crate serde_crate as serde;
 mod deduction;
 pub mod derive;
 mod descriptor;
+pub mod descriptors2;
 mod input;
 #[cfg(feature = "miniscript")]
 mod templates;