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Fix Wasm from rust docs (#1719)

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* Update Wasm from Rust docs

* oops

* oops x2
This commit is contained in:
Austin Abell
2020-05-18 07:58:21 -04:00
committed by GitHub
parent 463734b002
commit e40fd9d6ab
1 changed files with 32 additions and 23 deletions
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55
docs/lang-rust.md
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@@ -43,7 +43,7 @@ dependency in `Cargo.toml`:
```toml ```toml
[dependencies] [dependencies]
wasmtime = "0.12.0" wasmtime = "0.16.0"
``` ```
Next up let's write the code that we need to execute this wasm file. The Next up let's write the code that we need to execute this wasm file. The
@@ -120,7 +120,7 @@ some simple arithmetic from the environment.
(module (module
(import "" "log" (func $log (param i32))) (import "" "log" (func $log (param i32)))
(import "" "double" (func $double (param i32) (result i32))) (import "" "double" (func $double (param i32) (result i32)))
(func (export "run") (result i32) (func (export "run")
i32.const 0 i32.const 0
call $log call $log
i32.const 1 i32.const 1
@@ -138,29 +138,38 @@ looks like this:
```rust,no_run ```rust,no_run
# extern crate wasmtime; # extern crate wasmtime;
# use std::error::Error; use std::error::Error;
# use wasmtime::*; use wasmtime::*;
# fn main() -> Result<(), Box<dyn Error>> {
# let store = Store::default();
# let module = Module::new(&store, r#"
# (module
# (import "" "log" (func $log (param i32)))
# (import "" "double" (func $double (param i32) (result i32))))"#)?;
// First we can create our `log` function, which will simply print out the
// parameter it receives.
let log = Func::wrap(&store, |param: i32| {
println!("log: {}", param);
});
// Next we can create our double function which doubles the input it receives. fn main() -> Result<(), Box<dyn Error>> {
let double = Func::wrap(&store, |param: i32| param * 2); let store = Store::default();
# if false {
// When instantiating the module we now need to provide the imports to the let module = Module::from_file(&store, "hello.wat")?;
// instantiation process. This is the second slice argument, where each
// entry in the slice must line up with the imports in the module.
let instance = Instance::new(&module, &[log.into(), double.into()])?;
# Ok(())
# } # }
# let module = Module::new(&store, r#"(module (import "" "log" (func $log (param i32))) (import "" "double" (func $double (param i32) (result i32))) (func (export "run") i32.const 0 call $log i32.const 1 call $log i32.const 2 call $double call $log))"#)?;
// First we can create our `log` function, which will simply print out the
// parameter it receives.
let log = Func::wrap(&store, |param: i32| {
println!("log: {}", param);
});
// Next we can create our double function which doubles the input it receives.
let double = Func::wrap(&store, |param: i32| param * 2);
// When instantiating the module we now need to provide the imports to the
// instantiation process. This is the second slice argument, where each
// entry in the slice must line up with the imports in the module.
let instance = Instance::new(&module, &[log.into(), double.into()])?;
let run = instance
.get_func("run")
.expect("`run` was not an exported function");
let run = run.get0::<()>()?;
Ok(run()?)
}
``` ```
Note that there's a number of ways to define a `Func`, be sure to [consult its Note that there's a number of ways to define a `Func`, be sure to [consult its