CIS 194: Second Meeting (Week 01 Homework + Discussion of Week 02)

second.md

CIS 194: Second Meeting (12:00PM - 1:30PM PDT)

Agenda

• 12:00PM: Sandwiches
• Some useful tools
• Solicit presentation for Feb 5 (type classes)
• 12:30PM: Pain points from Week 1
• 12:50PM: Week 1 Homework Demo (Jeegar)

Tools

GHCi

• The :type command
• The :browse command
• The :load command
• Importing a module from a loaded package
• GHCi w/out importing modules

Stackage and Cabal

• LTS versions (stack.yml)
• Anatomy of a .cabal file
• Finding documentation for your LTS version

Debug.Trace

import Debug.Trace

example :: Int -> Int -> Int
example x y = trace ("x and y: " ++ (show x) ++ " " ++ (show y)) (x + y)

Typed Holes

sum :: [Int] -> Int
sum xs = foldr _f 10 xs

sum' :: _ -> Int
sum' xs = foldr (+) 10 xs

Weekly Presentations

I'm looking for someone who'd like to present a summary of the Week 5 lecture on February 4th.

Pain Points from the First Week

• Problems running the tests?
• Problems using the REPL?
• ???

Homework 1 Demo and Discussion