Hacker News Reader

Comment by donatj | Hacker News Reader

Go's lexical scoping and first class function/method's owe a lot to JS for leading the way IMHO. That said, it's "object" system is almost the complete reverse. JS is methods with data, Go is data with methods. It's an interesting contrast.

View on HN

Javascript leading the way? What are you talking about?

First class functions is a concept from mathematics and many programming languages had this feature way before javascript existed, and I simply don't understand exactly what concept of Go's lexical scoping resembles anything exclusive of javascript.

I don't understand the last paragraphs about methods with data and data with methods, but Go's structs resembles C's structs, binding methods to a struct is an thing I've only seen in Go, but maybe some other programming language had this before.

IIRC, the only difference in C++ between a struct and a class is the default visibility, and maybe some other bizarre quirky corner case or two.

Despite it technically not being in the Go lingo (the word "object" only appears once in the entire Go spec, and that's referring to composing arrays/slices together to get multi-dimensional arrays/slices), I generally don't kick myself too hard for referring to things in Go as "objects". They are. Sure, officially they're "structs with methods" (method is the official term), but given the diversity of other things the term "object" is applied to that's plenty close enough for me.

Go's structs resembles C's structs, binding methods to a struct is an thing I've only seen in Go, but maybe some other programming language had this before.

Oberon, probably others:

http://www.excelsior-usa.com/doc/xds/o2rep.html

> Go's lexical scoping and first class function/method's owe a lot to JS for leading the way IMHO.

I don't think this comment deserves the downvotes. JS deserves a lot of credit for doing scoping right in 1995, at a time when most popular languages (i.e. not Lisp or ML) were doing it wrong. (A notable exception was Perl 5, which did scoping right in 1994.) Thanks to JS, a lot of working programmers who would never be exposed to Lisp learned lexical scope. Remember that Emacs Lisp famously chose dynamic scope over lexical scope (a serious blunder) due to RMS's belief that lexical scope couldn't possibly be implemented in a performant way!

What languages without lexical scope are you thinking of?

Aside from literally only (pre-Common and Emacs) Lisp, I can't think of any language without lexical scope (outside some constructs etc).

[edit:] Or are you thinking of "only a single global namespace"? Even that exists only in otherwise highly restricted scripting languages, I think? ("Everything global" is technically lexical, but I see why you wouldn't want to call it that.)

Tcl, PHP, any language without closures.

How does PHP have dynamic scope? It's been ages since I touched it, but if I remember right...

Global is just a flat namespace. Functions have their own, separate flat namespace each. I tried the following in a REPL:

function two() { echo $a; }

function one() { $a = 1; two(); }

one();

as the standard dynamic scope example, and I get an "undefined variable" error. Did that use to be dynamic? (I wouldn't be surprised, though, especially given PHP's implementation history...)

There is an explicit "static" modifier that looks dynamic, but I couldn't get it to run that way. It seems to just retain state in recursive calls of the same function, or something?

[edit:] (And PHP doesn't predate Javascript, but regardless, "no first-class functions" isn't "no lexical scope".)

Yeah, I shouldn't have used the term "dynamic scope" there. PHP has dynamic environments that can be mutated at runtime, which languages like JS don't (well, outside of direct eval).

I argued for the design of and wrote the implementation for Go's lexical scoping and first class functions, and I can tell you they were in no way influenced by Javascript.

Scheme, Lisp, ML: yes. I'd written sizable programs in each of those, I'd worked on rewriting a programming languages course textbook with a professor in college, and I'd studied On Lisp. One of the initial test cases was Paul Graham's accumulator generator: https://github.com/golang/go/blob/0f4f2a6/test/closure.go

Javascript: no. At that time (Feb 2009) I doubt I even knew Javascript had lexically-scoped closures. I know I didn't buy 'Javascript: The Good Parts' until March 2010. Even today I don't think the fact that Javascript got closures right is particularly remarkable, except that, as Crockford demonstrates, that fact serves as the fundamental saving grace that enables forgiveness of many other problems.

I wasn't suggesting that JS directly influenced you. Rather my point was that JS was of the most important languages that brought lexical scoping and closures to the masses. By the time Go came around, it was considered a bog-standard feature, because of languages like JS (and others) that popularized it. That meant that programmers could more easily pick up Go.

Even if JS was not in the back of your mind, you have to admit that the design of "LISP in Cs clothing" (to quote Crockford) turned out nearly identical - certainly much closer than to Scheme, LISP or ML. And JS did it much earlier than Go. My point was that it owed developer comfort with the design to JavaScript, and not necessarily direct design influence.

Remember that Javascript was literally bashed together in just over a week. That's not a slur, that's a description of reality. Javascript is a minor miracle on its own, but even in that minor miracle, Brendon Eich did not have time to also prototype something brand new. Everything in Javascript was decades old when it was created. The prototype system was probably the craziest thing that went in, but even that was old, if not popular.

First class functions and lexical scoping have been actively used in programming languages since 4 decades prior to the invention of JS.

Mysteriously they gained popularity at the same time that JS did.

That is certainly not true, and therefore, not mysterious.

In fact this website, ycombinator, is the result of a nice pay day that Paul Graham enjoyed for selling web service he built in the 1990s using functional programming techniques... and it was not JS.

>> first class function/method's owe a lot to JS for leading the way

Javascript's lambdas were inspired by Scheme which has been around since the 70s.

"Remember, I was recruited to 'do Scheme', which felt like bait and switch in light of the Java deal brewing by the time I joined Netscape. My interest in languages such as Self informed a subversive agenda re: the dumbed down mission to make 'Java's kid brother', to have objects without classes. Likewise with first-class functions, which were inspired by Scheme but quite different in JS, especially JS 1.0." - Eich (on HN)

Reply on news.ycombinator.com