Should a programming language be powerful and let a programmer do a lot, or should it be safe and protect the programmer from bad mistakes? Contrary to what the title insinuates, these are not diametrically opposed attributes. Nevertheless, this is the mindset that underlies notions such as, “macros, manual memory management, etc. are power tools—they’re not supposed to be safe.” If safety and power are not necessarily opposed, why does this notion persist?| Lambda Land
There’s a neat paper Type Systems as Macros by Chang, Knauth, and Greenman [1] that describes how to implement a typed language using an untyped host language and macro expansion. The paper is neat, but I found the code hard to follow—the paper uses a compact notation that’s convenient for print, but not so much for reproducing on one’s own. This post is my attempt to implement and explain in more accessible terms what’s presented in the paper.| Lambda Land
Macros are tricky beasts. Most languages—if they have macros at all—usually include a huge “here there be dragons” warning to warn curious would-be macro programmers of the dangers that lurk ahead. What is it about macros that makes them so dangerous and unwieldy? That’s difficult to answer in general: there are many different macro systems with varying degrees of ease-of-use. Moreover, making macros easy to use safely is an open area of research—most languages that have macros do...| Technical Blog on Lambda Land