Function root_scope 

pub fn root_scope() -> Scope

Builds a fresh scope in which every built-in name is available.

The built-ins live in a parent scope, and the returned scope is an empty child of it, so user code can shadow a built-in name without changing it. The global names created by the bind and label built-ins go into the returned scope.

Every evaluation session should start from a scope created here (or from a child of one).

Examples

use swan_core::builtins::root_scope;
use swan_core::evaluator::eval;
use swan_core::lexer::Lexer;
use swan_core::parser::Parser;

let scope = root_scope();
let mut parser = Parser::new(Lexer::new("1+2"));
let ast = parser.parse();
assert_eq!(eval(&ast, &scope), swan_core::value::Value::Numb(3.0));