other/SevenLanguagesInSevenWeeks: 1-Ruby/code-blocks.rb comparison

Add some initial experiments with blocks

comparison

equal deleted inserted replaced

-:8d46064c9afc
+:61dfac9a058a
+#! /usr/bin/env ruby
+# Simple passing of code block
+3.times { puts 'Repeated string' }
+# Extending a class
+class Fixnum
+	def my_times
+		# We're in a number, so store it as an iterator
+		i = self
+		until i == 0
+			i = i - 1
+			# Magic happens here!
+			# Yield normally yields a value, but somehow we're executing a block…
+			yield
+		end
+	end
+end
+3.my_times { puts 'My repeated string' }
+# Blocks are objects, if you do it right - https://www.ruby-forum.com/topic/49018
+my_block = proc { puts 'I am a block' }
+puts my_block.class
+# Blocks can be passed around - "&var" says "this is a block"
+def call_block(&block)
+	block.call
+end
+def pass_block(&block)
+	call_block(&block)
+end
+pass_block { puts 'Inline block' }
+pass_block &my_block
+# Without the "&" we get "wrong number of arguments (1 for 0)" because
+# a block and an argument are different somehow. This is *not*
+# because we were trying to call "my_block" and pass what it returned (nil).
+# I tried. Calling a block definitely needs ".call"
+#
+# This page (https://mixandgo.com/blog/mastering-ruby-blocks-in-less-than-5-minutes)
+# makes it cleared: ANY method can take a block independent of its arguments.
+# That means that this works:
+def pass_var_block(block)
+	call_block(&block)
+end
+pass_var_block my_block

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