Question

I am trying to use a hash to display a form :

PREFIX_STR = "Prefix"
FIRST_STR = "First Name"

NEW_USER_HASH = Hash.new
NEW_USER_HASH[ "prefix" ] = { "label" => PREFIX_STR, "type" => "text_field" }
NEW_USER_HASH[ "first" ] = { "label" => FIRST_STR, "type" => "text_field" }

And in the new.html.erb, I have:

<%= form_for(resource, :as => resource_name, :url => registration_path(resource_name)) do |f| %>
  <%= devise_error_messages! %>

  <% NEW_USER_HASH.each do |column_name,field_info|  %>
    <div class="field">
      <%= f.label field_info["label"] %>
      <%= f.text_field column_name %>
    </div>
  <% end %>

This works fine, but instead of f.text_field, I want that to be what’s in field_info[“type”]. Nothing I tried worked. Any ideas?

Thanks

Answer 1

You might try f.send(field_into["type"], column_name).

(Edited to remove “to_sym“, which a commenter tells me is unnecessary (I thought send required symbols.)

Why this works: some_object.send("hello") is simply another way of writing some_object.hello. In Ruby, invoking a “method” on an object is actually a form of message passing — you’re sending a message to that object, and the object interprets it as a method invocation (or doesn’t — with ruby metaprogramming something that looks like a method call need not be).

In this case, you have an object f which represents a form_helper object, so when you call f.text_field, you’re sending a message to that object. By using f.send, you do the same thing, except you can generate the content of that message dynamically.