Class: Reading::Stats::Grouping

Inherits:
Object
  • Object
show all
Defined in:
lib/reading/stats/grouping.rb

Overview

The part of the query right after the operation, which groups the results, e.g. “by genre, rating”.

Class Method Summary collapse

Class Method Details

.group(input, items) ⇒ Hash

Determines which group(s) the input indicates, and then groups the Items accordingly. For the groups and their actions, see the constants below.

Parameters:

  • input (String) —

    the query string.

  • items (Array<Item>) —

    the Items on which to run the operation.

Returns:

  • (Hash) —

    the return value of the group action(s).



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# File 'lib/reading/stats/grouping.rb', line 12

def self.group(input, items)
  grouped_items = {}

  match = input.match(REGEX)

  if match
    group_names = match[:groups]
      .split(',')
      .tap { _1.last.sub!(/(\w)\s+\w+/, '\1') }
      .map(&:strip)
      .map { _1.delete_suffix('s') }
      .map(&:to_sym)

    if group_names.uniq.count < group_names.count
      raise InputError, "Each grouping can be applied only once in a query."
    end

    begin
      return group_hash(items, group_names)
    rescue InputError => e
      raise e.class, "#{e.message} in \"#{input}\""
    end
  end

  { all: items }
end