Function visit

common/ast/navigable.go:194–252

TODO: consider exposing a way to configure a limit for the max visit depth. It's possible that we could want to configure this on the NewExprVisitor() and through MatchDescendents() / MaxID().

(expr Expr, visitor Visitor, order visitOrder, depth, maxDepth int)

// It's possible that we could want to configure this on the NewExprVisitor()
// and through MatchDescendents() / MaxID().
func visit(expr Expr, visitor Visitor, order visitOrder, depth, maxDepth int) {
	if maxDepth > 0 && depth == maxDepth {
		return
	}
	if order == preOrder {
		visitor.VisitExpr(expr)
	}
	switch expr.Kind() {
	case CallKind:
		c := expr.AsCall()
		if c.IsMemberFunction() {
			visit(c.Target(), visitor, order, depth+1, maxDepth)
		}
		for _, arg := range c.Args() {
			visit(arg, visitor, order, depth+1, maxDepth)
		}
	case ComprehensionKind:
		c := expr.AsComprehension()
		visit(c.IterRange(), visitor, order, depth+1, maxDepth)
		visit(c.AccuInit(), visitor, order, depth+1, maxDepth)
		visit(c.LoopCondition(), visitor, order, depth+1, maxDepth)
		visit(c.LoopStep(), visitor, order, depth+1, maxDepth)
		visit(c.Result(), visitor, order, depth+1, maxDepth)
	case ListKind:
		l := expr.AsList()
		for _, elem := range l.Elements() {
			visit(elem, visitor, order, depth+1, maxDepth)
		}
	case MapKind:
		m := expr.AsMap()
		for _, e := range m.Entries() {
			if order == preOrder {
				visitor.VisitEntryExpr(e)
			}
			entry := e.AsMapEntry()
			visit(entry.Key(), visitor, order, depth+1, maxDepth)
			visit(entry.Value(), visitor, order, depth+1, maxDepth)
			if order == postOrder {
				visitor.VisitEntryExpr(e)
			}
		}
	case SelectKind:
		visit(expr.AsSelect().Operand(), visitor, order, depth+1, maxDepth)
	case StructKind:
		s := expr.AsStruct()
		for _, f := range s.Fields() {
			if order == preOrder {
				visitor.VisitEntryExpr(f)
			}
			visit(f.AsStructField().Value(), visitor, order, depth+1, maxDepth)
			if order == postOrder {
				visitor.VisitEntryExpr(f)
			}
		}
	}
	if order == postOrder {
		visitor.VisitExpr(expr)
	}