Add convenience constructor

src/ast.rs

@@ -62,6 +62,15 @@ pub struct VariableDeclarationStack
 
 impl VariableDeclarationStack
 {
+	pub fn new() -> Self
+	{
+		Self
+		{
+			free_variable_declarations: VariableDeclarations::new(),
+			bound_variable_declaration_stack: vec![],
+		}
+	}
+
 	pub fn find(&self, variable_name: &str) -> Option<std::rc::Rc<VariableDeclaration>>
 	{
 		for variable_declarations in self.bound_variable_declaration_stack.iter().rev()