Trait rhai::Func[−][src]

pub trait Func<ARGS, RET> {
    type Output;
    fn create_from_ast(self, ast: AST, entry_point: &str) -> Self::Output;

    fn create_from_script(
        self, 
        script: &str, 
        entry_point: &str
    ) -> Result<Self::Output, ParseError>;
}
Expand description

Trait to create a Rust closure from a script.

Not available under no_function.

Associated Types

Required methods

Create a Rust closure from an AST.

The Engine and AST are consumed and basically embedded into the closure.

Example

use rhai::{Engine, Func};               // use 'Func' for 'create_from_ast'

let engine = Engine::new();             // create a new 'Engine' just for this

let ast = engine.compile("fn calc(x, y) { x + len(y) < 42 }")?;

// Func takes two type parameters:
//   1) a tuple made up of the types of the script function's parameters
//   2) the return type of the script function

// 'func' will have type Box<dyn Fn(i64, String) -> Result<bool, Box<EvalAltResult>>> and is callable!
let func = Func::<(i64, &str), bool>::create_from_ast(
//                ^^^^^^^^^^^ function parameter types in tuple

                                            engine, // the 'Engine' is consumed into the closure
                                            ast,    // the 'AST'
                                            "calc"  // the entry-point function name
                                        );

func(123, "hello")? == false;           // call the anonymous function

Create a Rust closure from a script.

The Engine is consumed and basically embedded into the closure.

Example

use rhai::{Engine, Func};               // use 'Func' for 'create_from_script'

let engine = Engine::new();             // create a new 'Engine' just for this

let script = "fn calc(x, y) { x + len(y) < 42 }";

// Func takes two type parameters:
//   1) a tuple made up of the types of the script function's parameters
//   2) the return type of the script function

// 'func' will have type Box<dyn Fn(i64, String) -> Result<bool, Box<EvalAltResult>>> and is callable!
let func = Func::<(i64, &str), bool>::create_from_script(
//                ^^^^^^^^^^^ function parameter types in tuple

                                            engine, // the 'Engine' is consumed into the closure
                                            script, // the script, notice number of parameters must match
                                            "calc"  // the entry-point function name
                                        )?;

func(123, "hello")? == false;           // call the anonymous function

Implementors