The λ-calculus is often introduced by showing how to build a real programming language from it’s simple syntactic forms. In this series of post, I attempt to introduce it as a tool for modeling semantics. So if you’re opening Barendregt for the first time, trying to understand a lecture from a programming languages or functional programming class, or just starting to become involved in PL research, I hope this post will help you understand evaluation by substitution (β-reduction).
“Meaningful distinctions deserve to be maintained.” — Errett A. Bishop
Likewise, memorable quotations deserve to be read in context. In this spirit, I am happy to present the above “basic principle” in its context: Schizophrenia in contemporary mathematics (pdf)
Read on for a brief summary.
Christos Dimoulas is currently teaching a “History of Programming Languages” class at Harvard. The class is, as Christos writes, “definitely not about this”; instead, each meeting is a deep examination of a single, mature research topic, in terms of three to five key papers from the literature.
On Monday, I presented “the History of Actors” for the class. I’ve made the written-out talk notes and an annotated bibliography available here.
In the early days of the famous Emacs/Vim debates, Emacs was often ridiculed for its bulkiness (Eight Megabytes-of-RAM And Constantly Swapping, etc.). The computational power of our computer has grown much faster than Emacs’ bloat: it takes exactly one second to load on my machine. However, our workflows have also changed, and my workflow implies frequently starting new text editors — on each git commit for example, or when I use a Firefox extension to edit a textarea content in a proper editor.
In this blog post, I describe how to use emacsclient to reuse an existing Emacs process when creating a new editor window, which reduces editor startup times from 1s to 0.150s on my machine.
If you are interested in learning about the internals of the CompCert C compiler but would rather not read its source code, this post is for you.
The next edition of the New England Programming Language Seminar (NEPLS) will be held on Friday, October 7th at Northeastern University. Organizers are Gabriel Scherer and Max New. See you there!
Performance matters for software systems, but performance is not always easy to measure. At the PRL we recently had a scare with some unreliable measurements. Here is the story.
Racket is excellent for incrementally growing scripts into full-fledged programs.
This post steps through the evolution of one small program and highlights the
Racket tools that enable incremental advances.
This is part 3 of my tutorial for using the Racket FFI. You can find part 1
here
and part 2
here.
In this post, we will experiment with some low-level operations with pointers,
union types, and custom C types. The main takeaway will be the custom C types,
which let you define abstractions that hide the details of the C representation
when manipulating data in Racket.
This is part 2 of my tutorial on using the Racket FFI. If you haven’t read
part 1 yet, you can find it
here.
Update: part 3 is also now available
here.
Part 2 will continue with more Cairo examples. In this installment, I plan to
go over some more advanced FFI hacking such as handling computed argument
values, custom return arguments, and using C structs.