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63 lines
1.6 KiB
Rust
63 lines
1.6 KiB
Rust
// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
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//! This example shows you how to define ops in Rust and then call them from
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//! JavaScript.
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use deno_core::op_sync;
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use deno_core::Extension;
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use deno_core::JsRuntime;
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use deno_core::RuntimeOptions;
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fn main() {
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// Build a deno_core::Extension providing custom ops
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let ext = Extension::builder()
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.ops(vec![
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// An op for summing an array of numbers
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(
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"op_sum",
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// The op-layer automatically deserializes inputs
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// and serializes the returned Result & value
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op_sync(|_state, nums: Vec<f64>, _: ()| {
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// Sum inputs
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let sum = nums.iter().fold(0.0, |a, v| a + v);
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// return as a Result<f64, AnyError>
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Ok(sum)
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}),
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),
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])
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.build();
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// Initialize a runtime instance
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let mut runtime = JsRuntime::new(RuntimeOptions {
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extensions: vec![ext],
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..Default::default()
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});
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// Now we see how to invoke the op we just defined. The runtime automatically
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// contains a Deno.core object with several functions for interacting with it.
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// You can find its definition in core.js.
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runtime
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.execute_script(
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"<usage>",
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r#"
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// Print helper function, calling Deno.core.print()
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function print(value) {
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Deno.core.print(value.toString()+"\n");
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}
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const arr = [1, 2, 3];
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print("The sum of");
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print(arr);
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print("is");
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print(Deno.core.opSync('op_sum', arr));
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// And incorrect usage
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try {
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print(Deno.core.opSync('op_sum', 0));
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} catch(e) {
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print('Exception:');
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print(e);
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}
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"#,
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)
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.unwrap();
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}
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