Is it possible to access a nested dictionary from Dotliquid?

I was wondering if it was possible to access a nested dictionary with the dotliquid library.

What I have got so far is this:

type Document = {
    template : string
    elements : Map<string, obj>
}with  
    static member Test = {
        template = "{% for item in test %} {{ item[\"name\"] }} {% endfor %}"
        elements = 
            Map.empty 
            |> Map.add "test" ([Map.empty |> Map.add "name" "Foo"] :> obj) 
    }

let genTemplate = 
    let doc = Document.Test
    let template = Template.Parse(doc.template)
    template.Render(Hash.FromDictionary(doc.elements |> Map.toSeq |> dict))

The expected out of this would be: Foo but somewhat unsurprisingly I simply get an empty string. if I simply access item as opposed to item["name"] I get the output ["name", "Foo"]. So is there any way to do this in dotliquid? Any help would be most appreciated.

Solution

A relatively easy trick is to register a filter getName which then lets you access the name property of the nested dictionary using {{ item | getName }}. A filter can be written as an F# method:

type Filters() = 
  static member getName(map:Map<string, string>) = map.["name"]

Template.RegisterFilter(typeof<Filters>)

If you now use the filter in your test template. Note that depending on your configured DotLiquid naming convention, you might need to use get_name as the name (which is also the default):

type Document = 
  { template : string
    elements : Map<string, obj> }
  static member Test = 
    { template = "{% for item in test %} {{ item | get_name }} {% endfor %}"
      elements = 
          Map.empty 
          |> Map.add "test" ([Map.empty |> Map.add "name" "Foo"] :> obj) }

With this, you get the result you were expecting:

let genTemplate = 
    let doc = Document.Test
    let template = Template.Parse(doc.template)
    template.Render(Hash.FromDictionary(doc.elements |> Map.toSeq |> dict))

Unfortunately, I'm not sure if there is a way to create parameterized filters - it might be that you'll have to write something like getName for each key that you want to access.