The document discusses the concept of call graphs and message passing in programming, illustrating these ideas with example code in Ruby. It covers the definitions of classes and methods, including how objects can interact through message passing. Additionally, it mentions modules and methods for retrieving objects from AWS S3, emphasizing the structure of directed graphs.

1. FUTURE MEDIA LAB
ENGINEERING
LIGHTNING
TALKS

2. James Moriarty
Call Graphs

3. The “Call”
class A
def self.z
B.y
end
end
class B
def self.y
puts "hello world"
end
end
A.z # => "hello world"
“message passing is a
technique for invoking
behavior”
A -- y -> B
● A is the sender
● B is the receiver
● y is the message

4. The “Graph”
“a set of vertices and edges”

5. The “Call Graph”
class A
def self.x
B.new.y
end
end
class B
def y
1 + C.z do 1 end
end
end
class C
def self.z
yield
end
end

6. Things to look for

7. Universal Vertices

8. Directed Cyclic Graphs

9. Directed Acyclic Graphs
module Poto
module FileRepository
module AWS
class S3
def all(prefix:, page:, per_page:)
objects = client.objects(
page: page,
per_page: per_page,
prefix: prefix
)
FileCollectionMapper.new(objects).call
end
end
end
end
end

10. github.com/jamesmoriarty/call-graph