Struct rhai::AST

pub struct AST(_, _);

Compiled AST (abstract syntax tree) of a Rhai script.

Currently, AST is neither Send nor Sync. Turn on the sync feature to make it Send + Sync.

Implementations

impl AST

pub fn new(statements: Vec<Stmt>, lib: FunctionsLib) -> Self

Create a new AST.

pub fn merge(&self, other: &Self) -> Self

Merge two AST into one. Both AST's are untouched and a new, merged, version is returned.

The second AST is simply appended to the end of the first without any processing. Thus, the return value of the first AST (if using expression-statement syntax) is buried. Of course, if the first AST uses a return statement at the end, then the second AST will essentially be dead code.

All script-defined functions in the second AST overwrite similarly-named functions in the first AST with the same number of parameters.

Example

use rhai::Engine;

let engine = Engine::new();

let ast1 = engine.compile(r#"fn foo(x) { 42 + x } foo(1)"#)?;
let ast2 = engine.compile(r#"fn foo(n) { "hello" + n } foo("!")"#)?;

let ast = ast1.merge(&ast2);    // Merge 'ast2' into 'ast1'

// Notice that using the '+' operator also works:
// let ast = &ast1 + &ast2;

// 'ast' is essentially:
//
//    fn foo(n) { "hello" + n } // <- definition of first 'foo' is overwritten
//    foo(1)                    // <- notice this will be "hello1" instead of 43,
//                              //    but it is no longer the return value
//    foo("!")                  // returns "hello!"

// Evaluate it
assert_eq!(engine.eval_ast::<String>(&ast)?, "hello!");

pub fn clear_functions(&mut self)

Clear all function definitions in the AST.

pub fn retain_functions(&mut self)

Clear all statements in the AST, leaving only function definitions.

Trait Implementations

impl<'_> Add<&'_ AST> for &'_ AST

type Output = AST

The resulting type after applying the + operator.

fn add(self, rhs: Self) -> Self::Output

Performs the + operation.

impl Clone for AST

fn clone(&self) -> AST

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AST

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Default for AST

fn default() -> AST

Returns the "default value" for a type.