vendor/github.com/hashicorp/terraform/terraform/eval_filter.go

   1 package terraform
   2
   3 // EvalNodeFilterFunc is the callback used to replace a node with
   4 // another to node. To not do the replacement, just return the input node.
   5 type EvalNodeFilterFunc func(EvalNode) EvalNode
   6
   7 // EvalNodeFilterable is an interface that can be implemented by
   8 // EvalNodes to allow filtering of sub-elements. Note that this isn't
   9 // a common thing to implement and you probably don't need it.
  10 type EvalNodeFilterable interface {
  11         EvalNode
  12         Filter(EvalNodeFilterFunc)
  13 }
  14
  15 // EvalFilter runs the filter on the given node and returns the
  16 // final filtered value. This should be called rather than checking
  17 // the EvalNode directly since this will properly handle EvalNodeFilterables.
  18 func EvalFilter(node EvalNode, fn EvalNodeFilterFunc) EvalNode {
  19         if f, ok := node.(EvalNodeFilterable); ok {
  20                 f.Filter(fn)
  21                 return node
  22         }
  23
  24         return fn(node)
  25 }