From fcbf63e62c627deae76c1b8cb8c0876c536ed811 Mon Sep 17 00:00:00 2001
From: Jari Vetoniemi <jari.vetoniemi@indooratlas.com>
Date: Mon, 16 Mar 2020 18:49:26 +0900
Subject: Fresh start

---
 jni/ruby/sample/list.rb | 81 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 jni/ruby/sample/list.rb

(limited to 'jni/ruby/sample/list.rb')

diff --git a/jni/ruby/sample/list.rb b/jni/ruby/sample/list.rb
new file mode 100644
index 0000000..85899ce
--- /dev/null
+++ b/jni/ruby/sample/list.rb
@@ -0,0 +1,81 @@
+# Linked list example
+class MyElem
+  # object initializer called from Class#new
+  def initialize(item)
+    # @variables are instance variable, no declaration needed
+    @data = item
+    @succ = nil
+    @head = nil
+  end
+
+  def data
+    @data
+  end
+
+  def succ
+    @succ
+  end
+
+  # the method invoked by ``obj.data = val''
+  def succ=(new)
+    @succ = new
+  end
+end
+
+class MyList
+  def add_to_list(obj)
+    elt = MyElem.new(obj)
+    if @head
+      @tail.succ = elt
+    else
+      @head = elt
+    end
+    @tail = elt
+  end
+
+  def each
+    elt = @head
+    while elt
+      yield elt
+      elt = elt.succ
+    end
+  end
+
+  # the method to convert object into string.
+  # redefining this will affect print.
+  def to_s
+    str = "<MyList:\n";
+    for elt in self
+      # short form of ``str = str + elt.data.to_s + "\n"''
+      str += elt.data.to_s + "\n"
+    end
+    str += ">"
+    str
+  end
+end
+
+class Point
+  def initialize(x, y)
+    @x = x; @y = y
+    self
+  end
+
+  def to_s
+    sprintf("%d@%d", @x, @y)
+  end
+end
+
+# global variable name starts with `$'.
+$list1 = MyList.new
+$list1.add_to_list(10)
+$list1.add_to_list(20)
+$list1.add_to_list(Point.new(2, 3))
+$list1.add_to_list(Point.new(4, 5))
+$list2 = MyList.new
+$list2.add_to_list(20)
+$list2.add_to_list(Point.new(4, 5))
+$list2.add_to_list($list1)
+
+# parenthesises around method arguments can be ommitted unless ambiguous.
+print "list1:\n", $list1, "\n"
+print "list2:\n", $list2, "\n"
-- 
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