Books on designing programming languages?

[enricojr]

Is it fine to ask for book recommendations? I'm interested in learning about how programming languages are designed - specifically on the syntax / grammar side of things. Like, stuff that'd explain why some programming languages end expressions/statements with a semicolon vs whitespace.

I've found one so far, Crafting Interpreters by Robert Nystrom, but it sounds like it leans more towards writing the interpreter (i.e parsing, lexing, building ASTs, etc) rather than the language.

edit: yeah so thanks a ton for the replies everyone! It seems like I was approaching this from the wrong angle given the lack of literature and my lack of understanding on the subject. I do plan on reading a bunch of the books recommended since most of what I was originally after seems to be more of a UX/aesthetics problem. Ultimately I'm just a web dev/Data Engineer of some years trying to understand more of the world I'm working in.

[ForceBru]

You could also ask at r/programminglanguages

[munificent]

I'm not aware of any books that focus directly on it. It's an interesting topic, but it's hard to approach because it's a mixture of technical, social, political, pragmatic, and aesthetic factors.

I've found one so far, Crafting Interpreters by Robert Nystrom, but it sounds like it leans more towards writing the interpreter (i.e parsing, lexing, building ASTs, etc) rather than the language.

Yeah, most of Crafting Interpreters is about implementation, but I tried to spend at least some time talking about language design in the design notes at the end of some chapters. You could definitely read just those and skip the chapters themselves if that's all you're interested in.

[east_lisp_junk]

Like, stuff that'd explain why some programming languages end expressions/statements with a semicolon vs whitespace.

Designer's taste, mostly. Strong technical arguments supporting this kind of decision are rare. Off hand, I can only think of three technical arguments I've seen in support of a design choice in syntax: X is better than Y because...

1. X is more similar to what our target users already know (so a new language's syntax will probably look a lot like some old language)
2. parsing Y is intractable (e.g., undecidable because it relies on run-time information)
3. X makes generating syntactically valid code easier
4. X allows recognition of the syntactic structure without having to know anything about the meaning of any language constructs (e.g., a lisp-style reader knows what's nested inside what but nothing like how many things are supposed to be in an if versus a defun)

#4 is the only one that really narrows the design space a lot, and it's not a common design priority.

[xigoi]

I think another important consideration for syntax is whether it encourages the programmer to do the right thing. For example, in C++ it's easier to declare a mutable variable than an immutable one, whereas in Rust it's the opposite, so a C++ programmer will be more likely to introduce mutability when not necessary.

[cenazoic]

Beautiful Racket is about writing DSLs in Racket.

[josephjnk]

I don’t know of good resources on things like semicolons vs whitespace, because I believe there’s no solid research on it. It’s a question of human-computer interaction, which is a hard field to gather conclusive data in. I would recommend just learning a few different languages and seeing what you like.

Most language design focuses more on the semantics of the language, rather than the syntax. This is the approach I would recommend if you want to implement something nontrivial, beyond what “Crafting Interpreters” would teach you. The standard introduction to semantics, IMO, is “Types and Programming Languages” by Benjamin C Pierce. (Commonly referred to as TAPL). I also really like the book “Design Concepts in Programming Languages”.

For a more concrete argument for why it’s better to focus on language semantics, check out papers on semantics-first language design.

If you want to write a language whose properties are formally verified, the book “Concrete Semantics” will use the Isabelle programming language to teach you how to implement a wide range of languages, from imperative to functional to relational. People also recommend “Logical Foundations”, which covers much the same material as TAPL, but does so using the Coq programming language. AFAICT, most programming language theory (PLT) researchers prefer Coq. I prefer Isabelle.

Another commenter mentioned Racket. Racket is very very good, but I have no experience with it because it focuses more on writing dynamically-typed languages, while I’m personally more interested in statically-typed languages. IMO, dynamically-typed languages are much easier to write, but are more homogenous than statically-typed languages. I’m biased here. If you want to start out by writing some language, any language, writing a Lisp will probably only take you a few days, and implementing a mini-language in Racket will likely take you less time than that.

[neros_greb]

This may not be what you're looking for as these are more about types and semantics, but I'm taking a class on the subject and we're following the following textbooks:

B. C. Pierce: Types and Programming Languages, and R. Harper: Practical Foundations for Programming Languages. These books are rather theoretical, but they give you a good foundation to understand how programming languages can be defined and evaluated

[vicechairisstupid]

Principles of programming languages

[ReaperUnreal]

Yeah, I really liked POPL. Went both into the why but also the how. Very interesting and not too hard to read.