Hacker News Reader

Comment by hnthrowaway0328 | Hacker News Reader

I'm curious if there if any book or blogs that detail the design decisions, or the lack of, for some popular languages, from the perspective of language design and industry usage.

I could and have written a few toy interpreters, but I have no academic or industrial background (on the matter of language design), so it is useful to know why they put some features into a language, and why they don't. It is actually one of the most confusing parts of writing an interpreter for a toy language -- in all of my projects I simply pick a subset of an existing language I know about, e.g. Python or C.

View on HN

For Python, you can read the PEP documents - Python Enhancement Proposals - and see the discussion of what was suggested, pros and cons, work done to determine the preferred implementation, and the final decision.

https://peps.python.org/

To get the best historical sense, pick a language feature that has evolved in several steps over a number of years, e.g. async/await, type annotations, the GIL, etc.

For ordered dicts, for instance, which is topical because of [1] posted two weeks ago, the relevant PEPs are:

- PEP372: The original collections.ordereddict proposal in Python 3.1 [2]

- PEP468: Making kwargs ordered in Python 3.6 [3], which also made standard dicts ordered.

[1] https://news.ycombinator.com/item?id=45756058

[2] https://peps.python.org/pep-0372/

[3] https://peps.python.org/pep-0468/

It's pretty far back on my blog to-do list, but the key order guarantee that was solidified in 3.7 lost the opportunity for a further space optimization (for dicts where keys are frequently removed).

The Ada programming language has documentation about its design rationale that discusses the tradeoffs/options considered and why they made certain decisions. Really interesting even if you don’t use Ada since a lot of these decisions are made by every language’s designers.

[0] http://archive.adaic.com/standards/83rat/html/ratl-TOC.html

The Design and Evolution of C++ by Stroustrup is a fascinating book. It only covers the early years of C++, but that's perhaps what you're most interested in.

Reply on news.ycombinator.com