====== Week 10 ======

~~NOTOC~~

===== Channels, CSP, and Go =====

**//Continuing from where we left off last week//**

  * Hoare's 1978 CSP paper: https://spinroot.com/courses/summer/Papers/hoare_1978.pdf
    * Go implementation of examples from paper: https://godoc.org/github.com/thomas11/csp
  * Rob Pike's Google I/O 2012 - Go Concurrency Patterns: https://youtu.be/f6kdp27TYZs
  * Peter Welch's slides introducing CSP and occam-pi (but we will use Go this semester!)
    * [[courses:cs377-201951:welch-lectures:top|Occam-pi Lecture Notes]]
    * today: 
      * **//Objects Considered Harmful//** (slide 27 of motivation.pdf slides)
      * even though we won't be programming in occam-pi, I want to give you a flavor of it
      * because: 
        * ultimate lightweight processes!
        * composition! 
      * Legoland: slide 83-end of basics.pdf \\ \\ 
  * Demo and codewalk of csp-dining-philosophers.go
    * Go language features highlighted:
      * channels
      * select
    * Design basis for solution in Go: go routines (processes)
      * room (communicates with philosophers over channels)
        * for philosophers to enter/leave -- at most 4 at a time to prevent deadlocking, 5th philosopher blocks 
      * forks (communicate with philosophers over channels)
      * philosophers (communicate with forks over channels) \\ \\ 
  * Demo and codewalk: Sieve of Eratosthenes (Prime Number Sieve) 
    * copy the sample code from my directory to yours:
      * cd into the directory where you have your sample Go code
      * ''cp -r /home/mlsmith/cs377-examples/Go/sieve.go ~/''
    * Go language features highlighted:
      * Only one looping construct in Go: for loop 
        * all three parts are optional: init statement, conditional expression, post statement
      * channel declarations in function headers
        * can specify syntactically whether channel is for reading from: <code><-chan</code> or writing to: <code>chan<-</code>// //
  * Assignment 5 posted
    * Sort Pump Gophers {{sort-pump.pdf|PDF}}
    * Due: Friday, April 19th