CS Cabal

Toronto-based reading group that meets weekly to read computer science books and papers.

Currently reading: The Little Typer

GuildMeetup listings

Mastodon Social Hub

Mailing list Communication nexus

Code of Conduct Must read

Symbol Symbol on the Wall

July 10, 2016

By Scott

Hey everyone, great to see you all! Hope you all had a good wizard nap, er summer break!

Wasting no time we jumped right back into Chapter 31 “Symbols” of PFPL after a brief discussion concerning the overwhelming success rate of food based Kickstarter projects. Next week will be Chapter 32 “Fluid Binding” at the usual time and place, Friday at 6:30pm at gamma Space (Bento Miso).

Symbols provide us with a means for naming things and referencing them without placing any demands on their internal structure. This sounds straightforward but as we found working through the mathematics in this section they also give ample room for confusion.

We spent a lot of time working through some examples exploring how symbol references worked and the typing requirements of the “is” expressions. After that we returned to the start of the chapter and discussed mobility and the two different dynamic ranges of symbols; scoped to an expression or scope-free, which seem to loosely correspond with the demands of naming variables within a program or function and with storing data in a permanent store to be accessed later respectively.

We still have some open questions about the consequences of scope-free dynamics and if shadowing of symbols is possible, and are continuing to discuss it in the slack channel.

See you all next time! Scott