lib/red_amber/helper.rb in red_amber-0.3.0 vs lib/red_amber/helper.rb in red_amber-0.4.0

@@ -1,30 +1,35 @@
 # frozen_string_literal: true
 
 module RedAmber
-  # mix-in for the class DataFrame
+  # Mix-in for the class DataFrame
   module Helper
     private
 
     # If num is larger than 1 return 's' to be plural.
     #
-    # @param num [Numeric] some number.
-    # @return ['s', ''] return 's' if num is larger than 1.
+    # @param num [Numeric]
+    #   some number.
+    # @return ['s', '']
+    #   return 's' if num is larger than 1.
     #   Otherwise return ''.
+    #
     def pl(num)
       num > 1 ? 's' : ''
     end
 
-    # Parse the argments in an Array
-    #   and returns a parsed Array.
+    # Parse the argments in an Array and returns a parsed Array.
     #
     # @param args
     #   [<Integer, Symbol, true, false, nil, Array, Range, Enumerator, String, Float>]
     #   arguments.
-    # @param array_size [Integer] size of target Array to use in a endless Range.
-    # @return [<Integer, Symbol, true, false, nil>] parsed flat Array.
+    # @param array_size [Integer]
+    #   size of target Array to use in a endless Range.
+    # @return [<Integer, Symbol, true, false, nil>]
+    #   parsed flat Array.
     # @note This method is recursively called to parse.
+    #
     def parse_args(args, array_size)
       args.flat_map do |elem|
         case elem
         when Integer, Symbol, NilClass, TrueClass, FalseClass
           elem
@@ -44,13 +49,17 @@
       end
     end
 
     # Parse a Range to an Array
     #
-    # @param range [Range] Range to parse.
-    # @param array_size [Integer] size of target Array to use in a endless Range.
-    # @return [Array<Integer, Symbol, String>] parsed Array.
+    # @param range [Range]
+    #   range to parse.
+    # @param array_size [Integer]
+    #   size of target Array to use in a endless Range.
+    # @return [Array<Integer, Symbol, String>]
+    #   parsed Array.
+    #
     def parse_range(range, array_size)
       bg = range.begin
       en = range.end
       if [bg, en].any?(Integer)
         bg += array_size if bg&.negative?
@@ -68,6 +77,57 @@
       else
         Array(range)
       end
     end
   end
+
+  # rubocop:disable Layout/LineLength
+
+  # Helper for Arrow Functions
+  module ArrowFunction
+    module_function
+
+    # Find Arrow's compute function.
+    #
+    # {https://arrow.apache.org/docs/cpp/compute.html}
+    # @param function_name [Symbol]
+    #   function name.
+    # @return [Arrow::Function]
+    #   arrow compute function object.
+    # @example
+    #   RedAmber::ArrowFunction.find(:array_sort_indices)
+    #
+    #   # =>
+    #   #<Arrow::Function:0x7fa8838a0d80 ptr=0x7fa87e9b7320 array_sort_indices(array, {order=Ascending, null_placement=AtEnd}): Return the indices that would sort an array>
+    #
+    def find(function_name)
+      Arrow::Function.find(function_name)
+    end
+
+    # Show document of Arrow's compute function.
+    #
+    # @param function_name [Symbol]
+    #   function name.
+    # @return [String]
+    #   document of compute function object.
+    # @example
+    #   puts RedAmber::ArrowFunction.arrow_doc(:array_sort_indices)
+    #
+    #   # =>
+    #   array_sort_indices(array, {order=Ascending, null_placement=AtEnd}): Return the indices that would sort an array
+    #   ------------------
+    #   This function computes an array of indices that define a stable sort
+    #   of the input array.  By default, Null values are considered greater
+    #   than any other value and are therefore sorted at the end of the array.
+    #   For floating-point types, NaNs are considered greater than any
+    #   other non-null value, but smaller than null values.
+    #
+    #   The handling of nulls and NaNs can be changed in ArraySortOptions.
+    #
+    def arrow_doc(function_name)
+      f = find(function_name)
+      "#{f}\n#{'-' * function_name.size}\n#{f.doc.description}"
+    end
+  end
+
+  # rubocop:enable Layout/LineLength
 end