Class: Ptolemy::TOML::Toml

Inherits:
Treetop:: Runtime::SyntaxNode
  • Object
show all
Defined in:
lib/ptolemy/nodes.rb

Overview

Represents the top level node of TOML AST

Instance Method Summary collapse

Instance Method Details

#to_value ⇒ Hash

Evaluate the individual subtrees of the AST and then combine them to form the complete hash.

Returns:

  • (Hash) —

    a (possibly nested) hash containing all key value pairs.

Raises:

  • (ParseError) —

    if there are duplications in key groups or key value pairs.



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# File 'lib/ptolemy/nodes.rb', line 20

def to_value
  result = {}
  # Keep track of location under which all the key value pairs must be
  # stored. It gets modified when a key group is encountered.
  current = result
  # Store all key groups detected so that duplicates can be discovered.
  key_group_set = Set.new

  list.elements.map do |item|
    elem = item.elem
    if elem.is_a? KeyGroup
      # Reset current to root level. Key value groups always specify
      # nesting from root
      current = result
      key_group = elem.to_value
      if key_group_set.include? key_group
        raise ParseError, "Already defined [#{key_group}] before."
      end
      key_group_set.add key_group
      # If the key group is x.y.z.w, create the whole nested structure
      # in case it doesn't exist already.
      key_group.each do |key|
        current[key] = {} if current[key].nil?
        current = current[key]
      end
    else
      key, value = elem.to_value
      # Set value in hash, if it hasn't been set already.
      if current[key].nil?
        current[key] = value
      else
        raise ParseError, "Duplicate value for key:#{key}"
      end
    end
  end
  result
end