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by Barrin92 436 days ago
> Javascript is Lisp in C's clothes? On what basis?

On a lot of bases. Javascript has real lambdas, a sort of homoiconicity of code and data (hence JSON as a data format), also has the same dynamic take as lisps on "types belong to data". Rather than variables types belong to values. Brendan Eich's original idea was literally to "put scheme in the browser" and you can in fact pretty easily convert the Little Schemer to JS.

Saying two languages don't have much in common because they don't have the same syntax is a bit like saying we don't have much in common because we don't have the same hair color.

2 comments

> a sort of homoiconicity of code and data (hence JSON as a data format)

I get that "sort of" was an attempt to hedge, but really, this isn't even close. Homoiconicity here would be if all javascript source files were valid JSON documents. A weaker version would be if it were common to use JSON to represent an arbitrary javascript program, but I've never heard of that, either. (For a good explanation of this weaker sense of homoiconicity, this stackoverflow page [1] is pretty good.)

[1]: https://stackoverflow.com/questions/31733766/in-what-sense-a...

To use Clojure as an example of a language that is homoiconic, you can take any Clojure source file, send it to an EDN parser (EDN being Clojure's equivalent of JSON), and not only will parsing succeed, but the result will be a complete representation of the program (you could execute it if you wanted to). In contrast, if you try to send JS to a JSON parser, you'll get an error as soon as it hits a function definition, or a for loop, or an operator, or whatever.

But MacCarthy's original LISP 1 and LISP 1.5 do not have real lambdas. The lambda feature parametrizes a piece of code as a function literal, but doesn't capture anything.

What they have is code parsed to a data structure, which is then susceptible to manipulation by the program before being executed. JS has some dumb textual eval, like the Bourne shell.

They also have the concept of a symbol.

And only one value that is false.