# Brent Yorgey - CIS 194: Lazy evaluation (Highlights) ![rw-book-cover|256](https://readwise-assets.s3.amazonaws.com/static/images/article1.be68295a7e40.png) ## Metadata **Review**:: [readwise.io](https://readwise.io/bookreview/57953288) **Source**:: #from/readwise #from/reader **Zettel**:: #zettel/fleeting **Status**:: #x **Authors**:: [[Brent Yorgey]] **Full Title**:: CIS 194: Lazy evaluation **Category**:: #articles #readwise/articles **Category Icon**:: 📰 **URL**:: [www.seas.upenn.edu](https://www.seas.upenn.edu/~cis1940/spring13/lectures/06-laziness.html) **Host**:: [[www.seas.upenn.edu]] **Highlighted**:: [[2026-01-30]] **Created**:: [[2026-02-01]] ## Highlights - The slogan to remember is “*pattern matching drives evaluation*”. ([View Highlight](https://read.readwise.io/read/01kg6s6ptetde57ynh613shgg9)) ^983148179 - Notice how this definition of `(&&)` does not pattern-match on its second argument. Moreover, if the first argument is `False`, the second argument is entirely ignored. ([View Highlight](https://read.readwise.io/read/01kg6sb83x6wt49m7hebfdndh7)) ^983148613