Replacing if in ERB with a method

I want to replace this code

---
myyaml:
  me:
    :name: "John"
  text: |
    My name is <% if me %><%= me[:name] %><% end %>
---

With something like this:

---
myyaml:
  me:
    :name: "John"
  text: |
    My name is <%=greetings()%>
---

The idea is to define greetings function outside file and call as result_with_hash in ERB class.

The desired result is, obviously, My name is John.

One thing to note is ERB#result_with_hash states:(emphasis added)

result_with_hash(hash)

Render a template on a new toplevel binding with local variables specified by a Hash object.

So in your case you are trying to call a method greetings() which is fine and completely accessible but it negates any reason for using result_with_hash. If you wanted to you could use a local variable greeting instead and call the method to assign the value.

require 'yaml'
require 'erb'
yaml =<<DOC
---
myyaml:
  me:
    :name: "John"
  text: |
    My name is <%=greeting%>
---
DOC

# You used both String and Symbol keys would recommend picking one so this isn't as awkward
name = YAML.load(yaml).dig('myyaml','me',:name)

def greetings(name) 
  "#{name}!" 
end 

puts ERB.new(yaml).result_with_hash(greeting: greetings(name))
#=> ---
#myyaml:
#  me:
#    :name: "John"
#  text: |
#    My name is John!
#---

The other option would be to just use ERB#result rather than result_with_hash. Both result and result_with_hash will use the current binding so instance variables, local variables (not overridden by the Hash provided to result_with_hash) and methods are all accessible in the ERB template.

require 'yaml'
require 'erb'
yaml =<<DOC
---
myyaml:
  me:
    :name: "John"
  text: |
    My name is <%=greetings()%>
---
DOC

# You used both String and Symbol keys would recommend picking one so this isn't as awkward
@name = YAML.load(yaml).dig('myyaml','me',:name)

def greetings = "#{@name}!" 

puts ERB.new(yaml).result
#=> ---
#myyaml:
#  me:
#    :name: "John"
#  text: |
#    My name is John!
#---