Providing Helper function to walk a Shape

[harjitdotsingh]

There is no easy way to Walk the Shape object. Right now we get ambigious info from the Optimize calls.
Example

I hve the following code

type Collector []shape.Shape

func (t *Tagger) OptimizeShape(s shape.Shape) (shape.Shape, bool) {

    log.Println("||||", reflect.TypeOf(s))
    l, ok := s.(shape.Lookup)
    if !ok {
        t.Collector = append(t.Collector, s)
        return s, false // no changes to query
    }
    // generate a new tag
    t.n++
    tag := fmt.Sprintf("t%d", t.n)

    // replace with Save to tag of old shape
    return shape.Save{
        From: l,
        Tags: []string{tag},
    }, true
}

This returns ambigious information. Need a better way to Walk the Shape

[dennwc]

You can now walk the tree with a helper:

var arr []shape.Lookup
shape.Walk(s, func(s Shape) bool {
	if l, ok := s.(shape.Lookup); ok {
		arr = append(arr, l)
	}
	return true // continue
})

It will not produce duplicates, but will not allow modifications either.