Change value of node

[ostronom]

Hello. I am writing a JSON preprocessor, that applies some transformations to ast.Node and I've stumbled upon the impossibility to change value of ast.Node itself.

For example, if I've located a numeric node by path and I want to change its value to the result of some algebraic expression, there is currently no way of doing it, because it's not "Set", since there is no "key". The only solution is to backtrack node position in ASTree and change node value from there, but it involves a lot if code with lots of edge cases for such a task.

Is there a possibility of adding this in next versions or there is an easy way of doing this which I am not seeing?

[liuq19]

duplicated issue #730

[ostronom]

I am not sure that #730 refers to the same thing. Quite the opposite, i want to change value on current node, to which i have a pointer to.

[liuq19]

Could you show your expected coding example? Just like #730 to make the issue more clear

[ostronom]

I've imagined something like: func (n *ast.Node) SetValue[T any](v T) error { ... } to be exposed in API, because *s = ... trick:

1. hides the intent
2. isn't at all obvious
3. can introduce forward incompatibility, since we do not know if there are any links from other parts of sonic to this node and are we breaking anything with it or not

[AsterDY]

Since most of the time you get a *Node, you can just reset the pointer memory like *Node=ast.NewXX()

[liuq19]

I've imagined something like: func (n *ast.Node) SetValue[T any](v T) error { ... } to be exposed in API, because *s = ... trick:

1. hides the intent
2. isn't at all obvious
3. can introduce forward incompatibility, since we do not know if there are any links from other parts of sonic to this node and are we breaking anything with it or not

yeah, a generic type API about Get/Set will be easier to use, I think we will support it @AsterDY