Merge pull request #1034 from skandhas/pr-add-mruby-enumerable-ext

add mrbgem: mruby-enum-ext and some methods.

build_config.rb

@@ -23,6 +23,9 @@ MRuby::Build.new do |conf|
   # Use standard Kernel#sprintf method
   conf.gem "#{root}/mrbgems/mruby-sprintf"
 
+  # Use extensional Enumerable module
+  conf.gem "#{root}/mrbgems/mruby-enum-ext"
+
   # Use extensional String class
   conf.gem "#{root}/mrbgems/mruby-string-ext"
 

mrbgems/mruby-enum-ext/mrbgem.rake

@@ -0,0 +1,4 @@
+MRuby::Gem::Specification.new('mruby-enum-ext') do |spec|
+  spec.license = 'MIT'
+  spec.authors = 'mruby developers'
+end

mrbgems/mruby-enum-ext/mrblib/enum.rb

@@ -0,0 +1,85 @@
+##
+# Enumerable
+#
+module Enumerable
+  ##
+  # call-seq:
+  #    enum.drop(n)               -> array
+  #
+  # Drops first n elements from <i>enum</i>, and returns rest elements
+  # in an array.
+  #
+  #    a = [1, 2, 3, 4, 5, 0]
+  #    a.drop(3)             #=> [4, 5, 0]
+
+  def drop(n)
+    raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
+    raise ArgumentError, "attempt to drop negative size" if n < 0
+
+    ary = []
+    self.each {|e| n == 0 ? ary << e : n -= 1 }
+    ary
+  end
+
+  ##
+  # call-seq:
+  #    enum.drop_while {|arr| block }   -> array
+  #
+  # Drops elements up to, but not including, the first element for
+  # which the block returns +nil+ or +false+ and returns an array
+  # containing the remaining elements.
+  #
+  #    a = [1, 2, 3, 4, 5, 0]
+  #    a.drop_while {|i| i < 3 }   #=> [3, 4, 5, 0]
+
+  def drop_while(&block)
+    ary, state = [], false
+    self.each do |e|
+      state = true if !state and !block.call(e)
+      ary << e if state
+    end
+    ary
+  end
+
+  ##
+  # call-seq:
+  #    enum.take(n)               -> array
+  #
+  # Returns first n elements from <i>enum</i>.
+  #
+  #    a = [1, 2, 3, 4, 5, 0]
+  #    a.take(3)             #=> [1, 2, 3]
+
+  def take(n)
+    raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
+    raise ArgumentError, "attempt to take negative size" if n < 0
+
+    ary = []
+    self.each do |e|
+      break if ary.size >= n
+      ary << e
+    end
+    ary
+  end
+
+  ##
+  # call-seq:
+  #    enum.take_while {|arr| block }   -> array
+  #
+  # Passes elements to the block until the block returns +nil+ or +false+,
+  # then stops iterating and returns an array of all prior elements.
+  #
+  #
+  #    a = [1, 2, 3, 4, 5, 0]
+  #    a.take_while {|i| i < 3 }   #=> [1, 2]
+
+  def take_while(&block)
+    ary = []
+    self.each do |e|
+      return ary unless block.call(e)
+      ary << e
+    end
+    ary
+  end
+  
+end

mrbgems/mruby-enum-ext/test/enum.rb

@@ -0,0 +1,25 @@
+##
+# Enumerable(Ext) Test
+
+assert("Enumerable#drop") do
+  a = [1, 2, 3, 4, 5, 0]
+
+  assert_equal a.drop(3), [4, 5, 0]
+  assert_equal a.drop(6), []
+end
+
+assert("Enumerable#drop_while") do
+  a = [1, 2, 3, 4, 5, 0]
+  assert_equal a.drop_while {|i| i < 3 }, [3, 4, 5, 0]
+end
+
+assert("Enumerable#take") do
+  a = [1, 2, 3, 4, 5, 0]
+  assert_equal a.take(3), [1, 2, 3]
+end
+
+assert("Enumerable#take_while") do
+  a = [1, 2, 3, 4, 5, 0]
+  assert_equal a.take_while {|i| i < 3 }, [1, 2]
+end
+