variableDeclarator method
Implementation
Parser<VariableDeclaratorNode> variableDeclarator() => seq2(
ref0(identifier),
(ref1(token, '=') & ref0(expression))
.map((l) => l[1] as ExpressionNode)
.optional(),
).map2((name, init) => VariableDeclaratorNode(name: name, initializer: init));