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78 lines
2.0 KiB
Markdown
78 lines
2.0 KiB
Markdown
2 years ago
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# embed-nu
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*embed-nu* can be used to call [nu](https://github.com/nushell/nushell) scripts and expressions
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from within your rust application. This crate provides a wrapper around the nu engine to easily build
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the nu execution context, parse scripts and call functions. As this crate includes nu as a dependency
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calls to nu don't have the overhead of calling an external application.
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## Example Usage
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```rust
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use embed_nu::{rusty_value::RustyValue, CommandGroupConfig, Context, NewEmpty, PipelineData};
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fn main() {
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let mut ctx = Context::builder()
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.with_command_groups(CommandGroupConfig::default().all_groups(true))
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.add_parent_env_vars()
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.build()
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.unwrap();
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// eval a nu expression
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let pipeline = ctx
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.eval_raw(
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r#"echo "Hello World from this eval""#,
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PipelineData::empty(),
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)
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.unwrap();
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// print the pipeline of this expression. In this case
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// this pipeline contains the text of the echo expression
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// as it's the last expressin
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ctx.print_pipeline(pipeline).unwrap();
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// this eval put's the function definition of hello into scope
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ctx.eval_raw(
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r#"
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def hello [] {
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echo "Hello World from this script";
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echo # dummy echo so I don't have to print the output
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}
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"#,
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PipelineData::empty(),
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)
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.unwrap();
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// hello can now be called as a function
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ctx.call_fn("hello", [] as [String; 0]).unwrap();
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}
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```
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## Converting data into nu values
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This crate uses [rusty-value](https://github.com/Trivernis/rusty-value) to convert any rust
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data type into nu values.
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```rust
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use embed_nu::{rusty_value::RustyValue, IntoValue};
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// derive rusty value
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#[derive(RustyValue)]
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struct MyStruct {
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foo: String,
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bar: usize,
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}
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fn main() {
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let instance = MyStruct {
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foo: String::from("foo"),
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bar: 12
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};
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// convert this struct into a nu value
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// this is also done implicitely when passing the value to the nu context
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// as function arguments or variables
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let value = instance.into_value();
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dbg!(value);
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}
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```
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