[tonyarkles]

Going with the example in the article and the nominal purpose of it... how would you take what you’ve written above and parse/execute it without using eval.

I’m with you, generally. I have used CL off and on for the last 20 years, and when I come back to it it takes a solid week before I start “reading in Lisp”. It definitely doesn’t come naturally when you spend most of your time reading “C-type” syntax all day. But for some tasks it is an absolutely fantastic tool and doesn’t take that long to get back into.

[bbbobbb]

Genuine question since I might be missing something: how would you take the lisp version and parse/execute it without using something like eval?

[tonyarkles]

I'm not sure if you mean in JS or in CL, but it works basically the same way: deserialize it (not eval) and walk through the array, doing the exact same kind of steps they're doing in the article for the JS version. Build up a symbol table (or two, if your function names and variable names are in different namespaces). The evaluation rules are so simple and consistent that the logic required while walking the array is pretty tiny.

To do the same thing with Javascript code involves parsing into an AST and walking the that tree; the hard part is that the rules for walking that tree are dramatically more complicated. In the Lisp case, the AST and the original code look very similar; in the JS case, they diverge quite a bit (there's a ton of crazy things in the JS spec if you dig through it)