Feature parenthesis prop

[zhuliquan]

Add hasParen field for ast.Ndoe, which indicated add parenthesis when invoking String().
I've always thought that you should keep the parenthetical information of the node if the user input it.

[antonmedv]

Although I think this is a cool idea, it shouldn't be a part of AST. And default print node to string should not rely on it.

Usually in other programming languages this is done by additional linters with little bit more sophisticated parsers which also keeps information about new lines, brackets, types of quotes, comments.

Creating such linter for expr will the super nice.