How does JSON literals work

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How does JSON literals work

[eytan]

Hi Greg,
Awesome! JSON literals are a hacky way to implement dictionary/map-like objects. The syntax is something like:

x = @{"a": [1,2,3], "b": 2};
y = @[1,2,3];

where the stuff that comes after @ can't contain any PlanOut variables. Honestly, the JSON literal parser is pretty wonky, and we have been hoping that somebody with more experience writing parsers could implement a sane implementation of dictionaries, that would completely replace JSON literals, so that one could write things like:

weights1 = [1, 2, 1];
weights2 = [2,1,1];
y = {"US": weights1, "ES": weights2};

Is this something you would know how to do? If so, that would be great! Also, if you were to re-write the parser in PEG, would it be compatible with PEG.js?

Also, you may be interested in checking out the PlanOut editor (in planout/planout-editor/) -- I think it might motivate why we favor having a JS-based compiler :)

[GregBowyer]

Hi Greg,
Awesome! JSON literals are a hacky way to implement dictionary/map-like objects. The syntax is something like:

x = @{"a": [1,2,3], "b": 2};
y = @[1,2,3];

where the stuff that comes after @ can't contain any PlanOut variables. Honestly, the JSON literal parser is pretty wonky, and we have been hoping that somebody with more experience writing parsers could implement a sane implementation of dictionaries, that would completely replace JSON literals, so that one could write things like:

I could try to give it a shot in implementing a dict object, I might give that a shot once the grammar is done.

Is this something you would know how to do? If so, that would be great!

I could do it in a PEG, I generally hate writing classical grammars :P

Also, if you were to re-write the parser in PEG, would it be compatible with PEG.js?
I dont know if PEG.js takes grako EBNF format, but I dont think it would be hard to transliterate. Scanning quickly through the PEG.js documentation the one thing that might be troublesome is the lack of a cut operator.

Also, you may be interested in checking out the PlanOut editor (in planout/planout-editor/) -- I think it might motivate why we favor having a JS-based compiler :)

I have played with it a lot, its really neat. The rationale for me, for the python compiler is to have a compiler that can run inside a test-server that is responsible for farming out test jsons to systems that ask for them.

I opened a pull request #29 for where I am up to.