slides

require 'transit'

########################

writer = Transit::Writer.new(:json_verbose, STDOUT)
writer.write({:answer => 42})
# => "{\"~:answer\":42}"

reader = Transit::Reader.new(:json, StringIO.new("{\"~:answer\":42}"))
reader.read
# => {:answer=>42}

########################

writer = Transit::Writer.new(:json, STDOUT)
writer.write({:answer => 42})
# => "[\"^ \",\"~:answer\",42]"

reader = Transit::Reader.new(:json, StringIO.new("[\"^ \",\"~:answer\",42]"))
reader.read
# => {:answer=>42}

require 'transit'
require 'json'

reader = Transit::Reader.new(:json, StringIO.new({"~#unrecognized-tag" => [:some, :data]}.to_json))
reader.read
# => #<Transit::TaggedValue:... @tag="unrecognized-tag", @rep=["some", "data"]>

# semantic type: point
# tag: "point"
# rep: [int,int]

require 'ostruct'

Point = Struct.new(:x,:y) do
  def to_a; [x,y] end
end

class PointWriteHandler
  def tag(_) "point" end
  def rep(p) p.to_a end
  def string_rep(_) nil end
end

io = StringIO.new('','w+')
writer = Transit::Writer.new(:json_verbose, io, :handlers => {Point => PointWriteHandler.new})
writer.write(Point.new(37,42))
io.string
# => "{\"~#point\":[37,42]}\n"

class PointReadHandler
  def from_rep(rep)
    Point.new(*rep)
  end
end

reader = Transit::Reader.new(:json, StringIO.new(io.string), :handlers => {"point" => PointReadHandler.new})
reader.read
# => #<struct Point x=37, y=42>