Rails, MongoMapper nested Array in HAML form trouble - ruby-on-rails

Question

I'm getting
undefined method `Carrots' for # (referencing ln#18)
When trying to edit with the below form:
= form_for #harvest do |f|
- if #harvest.errors.any?
#error_explanation
%h2= "#{pluralize(#harvest.errors.count, "error")} prohibited this harvest from being saved:"
%ul
- #harvest.errors.full_messages.each do |msg|
%li= msg
.field
= f.label :created_at
= f.text_field :created_at, :disabled => true
%br
= f.label :photo
= f.text_field :photo
%h2 Crops
- #harvest.harvested_crops.each do |harvested_crop|
= f.label :harvested_crop['crop']
= f.select harvested_crop['crop'], Crop.all.collect {|p| [ p.name, p.id ] }, {:include_blank => ''}
= f.label :harvested_crop['amount']
= f.text_field harvested_crop['amount']
%br
.actions
= f.submit 'Save'
Using the data below:
{ "_id" : ObjectId("5067846f37bca62bccc3729e"), "user_id" : "5067844637bca62bccc3729c", "photo" : "carrotsnspuds.jpg", "harvested_crops" : [ { "crop" : "Carrots", "amount" : 1112.15 }, { "crop" : "Potatoes", "amount" : 3212.44 } ] }
I've tried related Stack Overflow questions for MongoMapper, Rails and Embedded documents but I am not having any luck, perhaps due to this being a nested Array rather than EmbeddedDocument. I'm not using Formtastic or anything yet, would just like to understand the syntax required here first.

Answer 1

This is definitely not efficient, but this allowed me to get the job done:
= form_for #harvest do |f|
- if #harvest.errors.any?
#error_explanation
%h2= "#{pluralize(#harvest.errors.count, "error")} prohibited this harvest from being saved:"
%ul
- #harvest.errors.full_messages.each do |msg|
%li= msg
.field
= f.label :created_at
= f.text_field :created_at, :disabled => true
%br
= f.label :photo
= f.text_field :photo
%h2 Crops
- x = 0
- #harvest.harvested_crops.each do |harvested_crop|
= f.fields_for "harvested_crops[]", harvested_crop do |hc|
%b Harvested Crop
%select{:name => "harvest[harvested_crops][" + x.to_s + "][crop]"}
- Crop.all.collect.each do |crop_name|
- if harvested_crop['crop'] == crop_name[:name]
%option{:selected => "selected", :value => crop_name[:name]}
= crop_name[:name]
- else
%option{:value => crop_name[:name]}
= crop_name[:name]
%b Amount
%input{:name => "harvest[harvested_crops][" + x.to_s + "][amount]", :value => harvested_crop['amount']}/
%br
- x += 1
%br
.actions
= f.submit 'Save'