Static BinaryOperator HashMap

[linuskmr]

This HashMap should be static to avoid creating it for every comparison of BinaryOperator.

fortytwo-lang/src/ast.rs

Lines 167 to 173 in d1d81e1

	let mut precedence = HashMap::new();
	precedence.insert(BinaryOperator::Less, 10);
	precedence.insert(BinaryOperator::Greater, 10);
	precedence.insert(BinaryOperator::Add, 20);
	precedence.insert(BinaryOperator::Subtract, 20);
	precedence.insert(BinaryOperator::Multiply, 30);
	precedence.insert(BinaryOperator::Divide, 30);

Maybe use lazy_static.