set up a typescript pipeline for interpreter

packages/interpreter/build.rs

@@ -0,0 +1,65 @@
+use std::{
+    fs::read_to_string,
+    hash::{DefaultHasher, Hash, Hasher},
+    process::Command,
+};
+
+fn main() {
+    // If any TS changes, re-run the build script
+    println!("cargo:rerun-if-changed=src/*.ts");
+
+    for entry in ["common", "form", "interpreter"].iter() {
+        gen_bindings(entry);
+    }
+}
+
+// okay...... so tsc might fail if the user doesn't have it installed
+// we don't really want to fail if that's the case
+// but if you started *editing* the .ts files, you're gonna have a bad time
+// so.....
+// we need to hash each of the .ts files and add that hash to the JS files
+// if the hashes don't match, we need to fail the build
+// that way we also don't need
+fn gen_bindings(name: &str) {
+    let contents = read_to_string(&format!("src/{name}.ts")).unwrap();
+    let generated = read_to_string(&format!("src/gen/{name}.js")).unwrap_or_default();
+    let hashed = hash_file(&contents);
+
+    // If the file is generated, and the hash is the same, we're good, don't do anything
+    if generated
+        .lines()
+        .next()
+        .unwrap_or_default()
+        .starts_with(&format!("// DO NOT EDIT THIS FILE. HASH: {}", hashed))
+    {
+        return;
+    }
+
+    // If the file is generated, and the hash is different, we need to generate it
+    let status = Command::new("tsc")
+        .arg(format!("src/{name}.ts"))
+        .arg("--outDir")
+        .arg("gen")
+        .arg("--target")
+        .arg("es6")
+        .status()
+        .unwrap();
+
+    if !status.success() {
+        panic!(
+            "Failed to generate bindings for {}. Make sure you have tsc installed",
+            name
+        );
+    }
+
+    // The file should exist, and now we need write the TS hash to the file
+    let generated = read_to_string(&format!("gen/{name}.js")).unwrap();
+    let generated = format!("// DO NOT EDIT THIS FILE. HASH: {}\n{}", hashed, generated);
+    std::fs::write(&format!("src/gen/{name}.js"), generated).unwrap();
+}
+
+fn hash_file(obj: &str) -> u64 {
+    let mut hasher = DefaultHasher::new();
+    obj.hash(&mut hasher);
+    hasher.finish()
+}