I'm learning how to use neon, but I don't understand a thing. If I try to execute this code:
#[macro_use]
extern crate neon;
use neon::vm::{Call, JsResult};
use neon::mem::Handle;
use neon::js::{JsInteger, JsNumber, JsString, JsObject, JsArray, JsValue, Object, Key};
use neon::js::error::{JsError, Kind};
fn test(call: Call) -> JsResult<JsArray> {
let scope = call.scope;
let js_arr: Handle<JsArray> = try!(try!(call.arguments.require(scope, 1)).check::<JsArray>());
js_arr.set(0, JsNumber::new(scope, 1000));
Ok(js_arr)
}
register_module!(m, {
m.export("test", test)
});
I get this error when I call js_arr.set
: This function takes 3 parameters but 2 were supplied.
I don't understand why since it's a JsArray
. Even Racer tells me that the set method takes 2 parameters. No matter what, js_arr.set
takes 3 parameters in this order: &mut bool
, neon::macro_internal::runtime::raw::Local
and neon::macro_internal::runtime::raw::Local
.
What's happening? I can't understand how JsArray
works.
As paulsevere says on a GitHub issue for Neon, import neon::js::Object
. In addition, do not import Key
, which also provides a set
method:
#[macro_use]
extern crate neon;
use neon::vm::{Call, JsResult};
use neon::js::{Object, JsArray, JsInteger, JsObject, JsNumber};
fn make_an_array(call: Call) -> JsResult<JsArray> {
let scope = call.scope; // the current scope for rooting handles
let array = JsArray::new(scope, 3);
array.set(0, JsInteger::new(scope, 9000))?;
array.set(1, JsObject::new(scope))?;
array.set(2, JsNumber::new(scope, 3.14159))?;
Ok(array)
}
register_module!(m, {
m.export("main", make_an_array)
});
This creates a brand new array. If you'd like to accept an array as the first argument to your function and then modify it, this works:
#[macro_use]
extern crate neon;
use neon::vm::{Call, JsResult};
use neon::js::{Object, JsArray, JsInteger, JsUndefined};
use neon::mem::Handle;
fn hello(call: Call) -> JsResult<JsUndefined> {
let scope = call.scope;
let js_arr: Handle<JsArray> = call.arguments.require(scope, 0)?.check::<JsArray>()?;
js_arr.set(0, JsInteger::new(scope, 1000))?;
Ok(JsUndefined::new())
}
register_module!(m, {
m.export("hello", hello)
});