Merge #340: serde: add stringify serializer over generic T:Display

a5f99ef serde: add stringify serializer over generic T:Display (Trevor Arjeski)

Pull request description:

  - Added a crate serde module and re-exported external serde crate from within it
  - Added a `simplicity::serializers::stringify` module that contains a generic serializer
    over `T: Display`, which can be used with
    `#[serde(with = "simplicity::serializers::stringify")]` over a struct field
  - Added a unit test that uses string values from Value's `value_display` test
  
  Resolves #330


ACKs for top commit:
  apoelstra:
    ACK a5f99ef; successfully ran local tests


Tree-SHA512: 79a9942e55a1ea01eb6d421adaa303e5477c2afa7039d4bf934d1f6e4faf7d317c21695c6e58032999414f7d5023d16efd816889b748cea77d90cf416ff452ea

Author: apoelstra

Cargo-recent.lock

@@ -212,6 +212,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3011d1213f159867b13cfd6ac92d2cd5f1345762c63be3554e84092d85a50bbd"
 
+[[package]]
+name = "itoa"
+version = "1.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92ecc6618181def0457392ccd0ee51198e065e016d1d527a7ac1b6dc7c1f09d2"
+
 [[package]]
 name = "jobserver"
 version = "0.1.34"
@@ -451,6 +457,19 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "serde_json"
+version = "1.0.149"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "83fc039473c5595ace860d8c4fafa220ff474b3fc6bfdb4293327f1a37e94d86"
+dependencies = [
+ "itoa",
+ "memchr",
+ "serde",
+ "serde_core",
+ "zmij",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -503,6 +522,7 @@ dependencies = [
  "miniscript",
  "santiago",
  "serde",
+ "serde_json",
  "simplicity-sys 0.6.1",
 ]
 
@@ -626,3 +646,9 @@ dependencies = [
  "quote",
  "syn",
 ]
+
+[[package]]
+name = "zmij"
+version = "1.0.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b8848ee67ecc8aedbaf3e4122217aff892639231befc6a1b58d29fff4c2cabaa"

Cargo.toml

@@ -40,6 +40,7 @@ getrandom = { version = "0.2", features = ["js"] }
 simplicity-sys = { version = "0.6.1", path = "./simplicity-sys", features = [
     "test-utils",
 ] }
+serde_json = "1.0.149"
 
 [workspace]
 members = ["simpcli", "simplicity-sys", "fuzz"]

src/bit_encoding/encode.rs

@@ -347,7 +347,7 @@ mod test {
             let mut w = BitWriter::from(&mut sink);
             encode_natural(n, &mut w).expect("encoding to vector");
             w.flush_all().expect("flushing");
-            let m = BitIter::from(sink.into_iter())
+            let m: usize = BitIter::from(sink.into_iter())
                 .read_natural(None)
                 .expect("decoding from vector");
             assert_eq!(n, m);

src/lib.rs

@@ -96,6 +96,8 @@ mod merkle;
 pub mod node;
 #[cfg(feature = "elements")]
 pub mod policy;
+#[cfg(feature = "serde")]
+pub mod serializers;
 pub mod types;
 mod value;
 

src/serializers/mod.rs

@@ -0,0 +1 @@
+pub mod stringify;

src/serializers/stringify.rs

@@ -0,0 +1,58 @@
+/// This module provides a generic serializer that serializes any type T:
+/// Display as a string and can be used with `#[serde(with =
+/// "simplicity::serializers::stringify")` over a struct field that implements
+/// `std::fmt::Display`.
+///
+///```rust
+/// use simplicity::Value;
+///
+/// #[derive(serde::Serialize)]
+/// struct Foo {
+///    #[serde(with = "simplicity::serializers::stringify")]
+///     v: Value,
+/// }
+///
+/// assert_eq!(
+///     serde_json::to_value(&Foo { v: Value::u1(0) }).unwrap(),
+///     serde_json::json!( { "v": "0b0" } )
+/// );
+///```
+use std::fmt::Display;
+
+use serde::Serializer;
+
+pub fn serialize<T, S>(value: &T, serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+    T: Display,
+{
+    serializer.serialize_str(&value.to_string())
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::Value;
+    use serde::Serialize;
+
+    #[test]
+    fn can_stringify_value() {
+        #[derive(Serialize)]
+        struct Foo {
+            #[serde(with = "crate::serializers::stringify")]
+            v: Value,
+        }
+
+        // values taken from Value's `value_display` test
+        let value_string_pairs = [
+            (Value::u1(0), "0b0"),
+            (Value::u1(1), "0b1"),
+            (Value::u4(6), "0x6"),
+        ];
+        for (v, want) in value_string_pairs {
+            assert_eq!(
+                serde_json::to_value(&Foo { v }).unwrap(),
+                serde_json::json!({ "v": want }),
+            );
+        }
+    }
+}