[descriptor] Add a macro to write descriptors from code

diff --git a/src/descriptor/dsl.rs b/src/descriptor/dsl.rs
new file mode 100644 (file)
index 0000000..a70bc75
--- /dev/null
+++ b/src/descriptor/dsl.rs
@@ -0,0 +1,234 @@
+// Magical Bitcoin Library
+// Written in 2020 by
+//     Alekos Filini <alekos.filini@gmail.com>
+//
+// Copyright (c) 2020 Magical Bitcoin
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+//! Descriptor DSL
+
+/// Domain specific language to write descriptors with code
+///
+/// This macro must be called in a function that returns a `Result<_, E: From<miniscript::Error>>`.
+///
+/// The `pk()` descriptor type (single sig with a bare public key) is not available, since it could
+/// cause conflicts with the equally-named `pk()` descriptor opcode. It has been replaced by `pkr()`,
+/// which stands for "public key root".
+///
+/// ## Example
+///
+/// Signature plus timelock, equivalent to: `sh(wsh(and_v(v:pk(...), older(...))))`
+///
+/// ```
+/// # use std::str::FromStr;
+/// # use miniscript::descriptor::DescriptorPublicKey;
+/// let my_key = DescriptorPublicKey::from_str("02e96fe52ef0e22d2f131dd425ce1893073a3c6ad20e8cac36726393dfb4856a4c").unwrap();
+/// let my_timelock = 50;
+/// let my_descriptor = bdk::desc!(sh ( wsh ( and_v (+v pk my_key), ( older my_timelock ))));
+/// # Ok::<(), bdk::Error>(())
+/// ```
+///
+/// 2-of-3 that becomes a 1-of-3 after a timelock has expired. Both `descriptor_a` and `descriptor_b` are equivalent: the first
+/// syntax is more suitable for a fixed number of items known at compile time, while the other accepts a
+/// [`Vec`] of items, which makes it more suitable for writing dynamic descriptors.
+///
+/// They both produce the descriptor: `wsh(thresh(2,pk(...),s:pk(...),sdv:older(...)))`
+///
+/// ```
+/// # use std::str::FromStr;
+/// # use miniscript::descriptor::DescriptorPublicKey;
+/// let my_key = DescriptorPublicKey::from_str("02e96fe52ef0e22d2f131dd425ce1893073a3c6ad20e8cac36726393dfb4856a4c").unwrap();
+/// let my_timelock = 50;
+///
+/// let descriptor_a = bdk::desc! {
+///     wsh (
+///         thresh 2, (pk my_key.clone()), (+s pk my_key.clone()), (+s+d+v older my_timelock)
+///     )
+/// };
+///
+/// let b_items = vec![
+///     bdk::desc!(pk my_key.clone()),
+///     bdk::desc!(+s pk my_key.clone()),
+///     bdk::desc!(+s+d+v older my_timelock),
+/// ];
+/// let descriptor_b = bdk::desc!( wsh ( thresh_vec 2, b_items ) );
+///
+/// assert_eq!(descriptor_a, descriptor_b);
+/// # Ok::<(), bdk::Error>(())
+/// ```
+#[macro_export]
+macro_rules! desc {
+    // Descriptor
+    ( bare ( $( $minisc:tt )* ) ) => ({
+        $crate::miniscript::Descriptor::<$crate::miniscript::descriptor::DescriptorPublicKey>::Bare($crate::desc!($( $minisc )*))
+    });
+    ( sh ( wsh ( $( $minisc:tt )* ) ) ) => ({
+        $crate::desc!(shwsh ($( $minisc )*))
+    });
+    ( shwsh ( $( $minisc:tt )* ) ) => ({
+        $crate::miniscript::Descriptor::<$crate::miniscript::descriptor::DescriptorPublicKey>::ShWsh($crate::desc!($( $minisc )*))
+    });
+    ( pkr $key:expr ) => ({
+        $crate::miniscript::Descriptor::<$crate::miniscript::descriptor::DescriptorPublicKey>::Pk($key)
+    });
+    ( pkh $key:expr ) => ({
+        $crate::miniscript::Descriptor::<$crate::miniscript::descriptor::DescriptorPublicKey>::Pkh($key)
+    });
+    ( wpkh $key:expr ) => ({
+        $crate::miniscript::Descriptor::<$crate::miniscript::descriptor::DescriptorPublicKey>::Wpkh($key)
+    });
+    ( sh ( wpkh ( $key:expr ) ) ) => ({
+        $crate::desc!(shwpkh ($( $minisc )*))
+    });
+    ( shwpkh ( $key:expr ) ) => ({
+        $crate::miniscript::Descriptor::<$crate::miniscript::descriptor::DescriptorPublicKey>::ShWpkh($key)
+    });
+    ( sh ( $( $minisc:tt )* ) ) => ({
+        $crate::miniscript::Descriptor::<$crate::miniscript::descriptor::DescriptorPublicKey>::Sh($crate::desc!($( $minisc )*))
+    });
+    ( wsh ( $( $minisc:tt )* ) ) => ({
+        $crate::miniscript::Descriptor::<$crate::miniscript::descriptor::DescriptorPublicKey>::Wsh($crate::desc!($( $minisc )*))
+    });
+
+    // Modifiers
+    ( +a $( $inner:tt )* ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Alt(std::sync::Arc::new($crate::desc!($( $inner )*))))?
+    });
+    ( +s $( $inner:tt )* ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Swap(std::sync::Arc::new($crate::desc!($( $inner )*))))?
+    });
+    ( +c $( $inner:tt )* ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Check(std::sync::Arc::new($crate::desc!($( $inner )*))))?
+    });
+    ( +d $( $inner:tt )* ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::DupIf(std::sync::Arc::new($crate::desc!($( $inner )*))))?
+    });
+    ( +v $( $inner:tt )* ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Verify(std::sync::Arc::new($crate::desc!($( $inner )*))))?
+    });
+    ( +j $( $inner:tt )* ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::NonZero(std::sync::Arc::new($crate::desc!($( $inner )*))))?
+    });
+    ( +n $( $inner:tt )* ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::ZeroNotEqual(std::sync::Arc::new($crate::desc!($( $inner )*))))?
+    });
+    ( +t $( $inner:tt )* ) => ({
+        $crate::desc!(and_v ( $( $inner )* ), ( true ) )
+    });
+    ( +l $( $inner:tt )* ) => ({
+        $crate::desc!(or_i ( false ), ( $( $inner )* ) )
+    });
+    ( +u $( $inner:tt )* ) => ({
+        $crate::desc!(or_i ( $( $inner )* ), ( false ) )
+    });
+
+    // Miniscript
+    ( true ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::True)?
+    });
+    ( false ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::False)?
+    });
+    ( pk_k $key:expr ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::PkK($key))?
+    });
+    ( pk $key:expr ) => ({
+        $crate::desc!(+c pk_k $key)
+    });
+    ( pk_h $key_hash:expr ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::PkH($key_hash))?
+    });
+    ( after $value:expr ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::After($value))?
+    });
+    ( older $value:expr ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Older($value))?
+    });
+    ( sha256 $hash:expr ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Sha256($hash))?
+    });
+    ( hash256 $hash:expr ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Hash256($hash))?
+    });
+    ( ripemd160 $hash:expr ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Ripemd160($hash))?
+    });
+    ( hash160 $hash:expr ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Hash160($hash))?
+    });
+    ( and_v ( $( $a:tt )* ), ( $( $b:tt )* ) ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::AndV(
+            std::sync::Arc::new($crate::desc!($( $a )*)),
+            std::sync::Arc::new($crate::desc!($( $b )*)),
+        ))?
+    });
+    ( and_b ( $( $a:tt )* ), ( $( $b:tt )* ) ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::AndB(
+            std::sync::Arc::new($crate::desc!($( $a )*)),
+            std::sync::Arc::new($crate::desc!($( $b )*))),
+        )?
+    });
+    ( and_or ( $( $a:tt )* ), ( $( $b:tt )* ), ( $( $c:tt )* ) ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::AndOr(
+            std::sync::Arc::new($crate::desc!($( $a )*)),
+            std::sync::Arc::new($crate::desc!($( $b )*)),
+            std::sync::Arc::new($crate::desc!($( $c )*)),
+        ))?
+    });
+    ( or_b ( $( $a:tt )* ), ( $( $b:tt )* ) ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::OrB(
+            std::sync::Arc::new($crate::desc!($( $a )*)),
+            std::sync::Arc::new($crate::desc!($( $b )*)),
+        ))?
+    });
+    ( or_d ( $( $a:tt )* ), ( $( $b:tt )* ) ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::OrD(
+            std::sync::Arc::new($crate::desc!($( $a )*)),
+            std::sync::Arc::new($crate::desc!($( $b )*)),
+        ))?
+    });
+    ( or_c ( $( $a:tt )* ), ( $( $b:tt )* ) ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::OrC(
+            std::sync::Arc::new($crate::desc!($( $a )*)),
+            std::sync::Arc::new($crate::desc!($( $b )*)),
+        ))?
+    });
+    ( or_i ( $( $a:tt )* ), ( $( $b:tt )* ) ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::OrI(
+            std::sync::Arc::new($crate::desc!($( $a )*)),
+            std::sync::Arc::new($crate::desc!($( $b )*)),
+        ))?
+    });
+    ( thresh_vec $thresh:expr, $items:expr ) => ({
+        let items = $items.into_iter().map(std::sync::Arc::new).collect();
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Thresh($thresh, items))?
+    });
+    ( thresh $thresh:expr $(, ( $( $item:tt )* ) )+ ) => ({
+        let mut items = vec![];
+        $(
+            items.push(std::sync::Arc::new($crate::desc!($( $item )*)));
+        )*
+
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Thresh($thresh, items))?
+    });
+    ( multi $thresh:expr, $keys:expr ) => ({
+        $crate::miniscript::Miniscript::from_ast($crate::miniscript::miniscript::decode::Terminal::Multi($thresh, $keys))?
+    });
+}

diff --git a/src/descriptor/mod.rs b/src/descriptor/mod.rs
index d75cdbfdd43da7e5ac644818b906c95792e303d6..51ee48d9f2a70957a8704ed1a2f71eb9bb148d4c 100644 (file)
--- a/src/descriptor/mod.rs
+++ b/src/descriptor/mod.rs
@@ -43,6 +43,7 @@ pub use miniscript::{
 };
 
 pub mod checksum;
+mod dsl;
 pub mod error;
 pub mod policy;