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0 pointsxscott4y ago0 comments

It's trivial for you, but are you sure you've got the OPs best interest at heart? Remember, you're trying to help someone else here.

I think the magic is in getting the interpreter to work, and depending on the personality, that might be what's motivating.

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6 comments · 2 top-level

coryrc4y ago· 4 in thread

It's really trivial for everyone. To start with you only need three classes of characters: parentheses, whitespace, and everything else defines a symbol.

I bought the dragon book long ago. I got about halfway through and it was still on parsing! What a waste. That's not a problem for s-expressions.

xscottOP4y ago

> I bought the dragon book long ago.

That makes me think you might've forgotten what it's like to be a beginner. Imagine teaching a high school student and that every other word you're using doesn't make complete sense to them yet.

arinlen4y ago

> That makes me think you might've forgotten what it's like to be a beginner.

Let's put things in perspective: the parser bit of putting together your own lisp is by far the easiest task of all.

Complaining that parsing lisp is hard to a beginner but everything else is accessible makes no sense at all. I mean, a parser for s-expressions requires what? Five or six terminal tokens and three or four non-terminal tokens? That's less than 50loc.

morelisp4y ago

Assuming the developer is competent in their language of choice should rule out anyone who can't write a Lisp parser in their language of choice.

If you're not undertaking this to learn how to write a Lisp, which includes writing a parser, what's the point? Get this tribe 3 shit out of here...

1 more reply

JohnHaugeland4y ago

imagine thinking the difference between parsing a string and using a pre-parsed datastructure was "trivial for everyone" because you could count off how many classes of character were involved

one major difference is that you don't have to write the parser at all the other way

arinlen4y ago

> It's trivial for you, but are you sure you've got the OPs best interest at heart?

It's trivial to anyone.

Furthermore, there are already s-expression parsers out there.

Suggesting JSON is simply poor, ill-thought out advice.

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