Struct moon_script::engine::Engine

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pub struct Engine { /* private fields */ }

Expand description

Scripting engine, it allows to create runnable ASTs, and also to give functions and constant values for said scripts

Implementations§

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impl Engine

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pub fn new() -> Self

Creates a new empty Engine containing just basic functions, like println or binary operators

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pub fn add_constant<Name: ToString, Value: Into<Constant>>( &mut self, name: Name, value: Value, ) -> Option<Constant>

Adds a constant with a value

use moon_script::{ContextBuilder, Engine};
let mut engine = Engine::new();
engine.add_constant("MY_CONSTANT", 15);
let runnable_ast = engine.parse(r###"
    return MY_CONSTANT;
"###, ContextBuilder::default()).unwrap();
let result : i32 = runnable_ast.executor().execute().unwrap().try_into().unwrap();
assert_eq!(15, result);

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pub fn add_function<Function: Into<FunctionDefinition>>( &mut self, function_definition: Function, )

Adds a function with a name

use moon_script::{ContextBuilder, Engine, FunctionDefinition};
let mut engine = Engine::new();
engine.add_function(FunctionDefinition::new("say_hi_and_return_number", ||{
    println!("Hi!");
    return 5;
}));
let runnable_ast = engine.parse(r###"
    return say_hi_and_return_number();
"###, ContextBuilder::default()).unwrap();
let result : i32 = runnable_ast.executor().execute().unwrap().try_into().unwrap();
assert_eq!(5, result);

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pub fn parse<'input>( &self, input: &'input str, context_builder: ContextBuilder, ) -> Result<AST, ParsingError<'input>>

Parses a script into an AST using a specific context

Adds a function with a name

use moon_script::{InputVariable, ContextBuilder, Engine, FunctionDefinition};

let mut engine = Engine::new();
engine.add_function(FunctionDefinition::new("add_five", |num:u8| {
    return num + 5;
}));

let context = ContextBuilder::new()
    .with_variable(InputVariable::new("ten").value(10));


let runnable_ast = engine.parse(r###"
    return add_five(ten);
"###, context).unwrap();
let result : i32 = runnable_ast.executor().execute().unwrap().try_into().unwrap();
assert_eq!(15, result);