Initial reorg.

This is largely the same as #305, but updated for the current tree.

crates/api/examples/gcd.rs

@@ -0,0 +1,43 @@
+//! Example of instantiating of the WebAssembly module and
+//! invoking its exported function.
+
+use anyhow::{format_err, Result};
+use std::fs::read;
+use wasmtime_api::*;
+
+fn main() -> Result<()> {
+    let wasm = read("examples/gcd.wasm")?;
+
+    // Instantiate engine and store.
+    let engine = HostRef::new(Engine::default());
+    let store = HostRef::new(Store::new(&engine));
+
+    // Load a module.
+    let module = HostRef::new(Module::new(&store, &wasm)?);
+
+    // Find index of the `gcd` export.
+    let gcd_index = module
+        .borrow()
+        .exports()
+        .iter()
+        .enumerate()
+        .find(|(_, export)| export.name().to_string() == "gcd")
+        .unwrap()
+        .0;
+
+    // Instantiate the module.
+    let instance = HostRef::new(Instance::new(&store, &module, &[])?);
+
+    // Invoke `gcd` export
+    let gcd = instance.borrow().exports()[gcd_index]
+        .func()
+        .expect("gcd")
+        .clone();
+    let result = gcd
+        .borrow()
+        .call(&[Val::from(6i32), Val::from(27i32)])
+        .map_err(|e| format_err!("call error: {:?}", e))?;
+
+    println!("{:?}", result);
+    Ok(())
+}