From eb088aa4911f5b450c2ca74a2f00bfe8f47d4202 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Fri, 29 May 2020 11:08:12 +0200
Subject: [PATCH] Experimentation with extensibility, such as it is

---
 implementations/rust/examples/Makefile        | 10 ++++
 .../rust/examples/extensibility.rs            | 53 +++++++++++++++++++
 implementations/rust/examples/known-data.bin  |  1 +
 implementations/rust/examples/known-data.txt  |  7 +++
 .../rust/examples/unknown-data.bin            |  1 +
 .../rust/examples/unknown-data.txt            |  8 +++
 6 files changed, 80 insertions(+)
 create mode 100644 implementations/rust/examples/Makefile
 create mode 100644 implementations/rust/examples/extensibility.rs
 create mode 100644 implementations/rust/examples/known-data.bin
 create mode 100644 implementations/rust/examples/known-data.txt
 create mode 100644 implementations/rust/examples/unknown-data.bin
 create mode 100644 implementations/rust/examples/unknown-data.txt

diff --git a/implementations/rust/examples/Makefile b/implementations/rust/examples/Makefile
new file mode 100644
index 0000000..943d1e9
--- /dev/null
+++ b/implementations/rust/examples/Makefile
@@ -0,0 +1,10 @@
+BINARY_FILES=known-data.bin unknown-data.bin
+
+all: $(BINARY_FILES)
+
+%.bin: %.txt Makefile
+	racket ../../racket/preserves/preserves/tool.rkt --atob --no-annotations < $< > $@.tmp || (rm -f $@.tmp; false)
+	mv $@.tmp $@
+
+clean:
+	rm -f $(BINARY_FILES)
diff --git a/implementations/rust/examples/extensibility.rs b/implementations/rust/examples/extensibility.rs
new file mode 100644
index 0000000..6e3aae6
--- /dev/null
+++ b/implementations/rust/examples/extensibility.rs
@@ -0,0 +1,53 @@
+use preserves::{de, value, value::decoder};
+use serde::{Serialize, Deserialize};
+use std::fs::File;
+use std::io::Error;
+
+#[derive(Debug, Serialize, Deserialize, PartialEq)]
+enum Fruit {
+    Apple(Colour),
+    Pear(Variety),
+    Banana(Weight, Colour, u8),
+
+    // Peach,
+
+    #[serde(other)]
+    Unknown,
+}
+
+#[derive(Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename = "kilograms")]
+struct Weight(f32);
+
+#[derive(Debug, Serialize, Deserialize, PartialEq)]
+struct Colour {
+    name: String,
+}
+
+#[derive(Debug, Serialize, Deserialize, PartialEq)]
+enum Variety {
+    Conference,
+    Bosc,
+    European,
+    Anjou,
+}
+
+fn try_file(kind: &str, path: &str) -> Result<(), Error> {
+    let fruits_value = decoder::from_read(&mut File::open(path)?).demand_next()?;
+    println!("{:?}", fruits_value);
+
+    let fruits1: Vec<Fruit> = value::de::from_value(&fruits_value)?;
+    println!("(via generic decoding) {}: {:?}", kind, fruits1);
+
+    let fruits2: Vec<Fruit> = de::from_read(&mut File::open(path)?)?;
+    println!("(direct from binary)   {}: {:?}\n", kind, fruits2);
+
+    assert_eq!(fruits1, fruits2);
+    Ok(())
+}
+
+fn main() -> Result<(), Error> {
+    try_file("KNOWN", "examples/known-data.bin")?;
+    try_file("UNKNOWN", "examples/unknown-data.bin")?;
+    Ok(())
+}
diff --git a/implementations/rust/examples/known-data.bin b/implementations/rust/examples/known-data.bin
new file mode 100644
index 0000000..d7173a3
--- /dev/null
+++ b/implementations/rust/examples/known-data.bin
@@ -0,0 +1 @@
+”‚uApple‚vColourSred‚uApple‚vColourUgreen„vBanana‚ykilograms?ž¸Që…¸‚vColourXbrownish5‚tPearzConference
\ No newline at end of file
diff --git a/implementations/rust/examples/known-data.txt b/implementations/rust/examples/known-data.txt
new file mode 100644
index 0000000..96ed208
--- /dev/null
+++ b/implementations/rust/examples/known-data.txt
@@ -0,0 +1,7 @@
+@<EmacsMode "-*- preserves -*-">
+[
+  <Apple <Colour "red">>
+  <Apple <Colour "green">>
+  <Banana <kilograms 0.12> <Colour "brownish"> 5>
+  <Pear <Conference>>
+]
diff --git a/implementations/rust/examples/unknown-data.bin b/implementations/rust/examples/unknown-data.bin
new file mode 100644
index 0000000..233fcbb
--- /dev/null
+++ b/implementations/rust/examples/unknown-data.bin
@@ -0,0 +1 @@
+•‚uApple‚vColourSreduPeach‚uApple‚vColourUgreen…vBanana‚ykilograms?ž¸Që…¸‚vColourXbrownish5˛xripenesswSquishy‚tPearzConference
\ No newline at end of file
diff --git a/implementations/rust/examples/unknown-data.txt b/implementations/rust/examples/unknown-data.txt
new file mode 100644
index 0000000..fce3d3a
--- /dev/null
+++ b/implementations/rust/examples/unknown-data.txt
@@ -0,0 +1,8 @@
+@<EmacsMode "-*- preserves -*-">
+[
+  <Apple <Colour "red">>
+  <Peach>
+  <Apple <Colour "green">>
+  <Banana <kilograms 0.12> <Colour "brownish"> 5 {ripeness: <Squishy>}>
+  <Pear <Conference>>
+]