Are the JSON arrays LL(1) parsable?

Question

I've heard if you parse something LL(1) it's faster so I was wondering if you want to parse a JSON string can this be done by using a LL(1) parser

Breakaway

Answer 1

Yes, they are, since there's no ambiguity in the JSON grammar.

Wightman

In addition, you can check out my implementation which is hopefully not too difficult to understand. – Wightman

While it's true that JSON is LL(1), this answer implies that all non-ambiguous grammars are LL(1). This is not correct. LL(1) grammars are a subset of the non-ambiguous grammars. For example, left-recursive grammars like "A -> A a | a" are not LL(1). – Deflected

@JoshHaberman It is my understanding that simple transformations on a left-recursive grammer will make it LL(1). – Sheldonshelduck

@JoshHaberman any reference tha JSON is LL(1)? – Rhetorician

Answer 2

Yes, it is. See to yourself that the implementation of a parser for JSON string can be done with a automaton consisting of no more than 1 token. In other words, there exists a Markov chain solution for it.

Taperecord

Answer 3

array:

[ ] | [ elements ]

elements:

value | value , elements

it seems not LL(1) to me. Clear cannot parse on "value"

What if this way?

array: [ array1 ]
array1: <eps> | elements
elements: value elements1
elements1: <eps> | , elements

Les

Answer 4

Yes, it is LL(1) parsable. It has a context-free grammar and no ambiguity.

Pupa

That doesn't make it LL(1). – Foetus

A grammar is LL(1) if an LL(1) parser can be constructed for it. Not all unambiguous context-free grammars have LL(1) parsers. Sorry if I'm struggling a little here, but I'm not sure what else to say other than to direct you to the Wikipedia page for LL_parser – Foetus

Answer 5

array:

[] |
[ elements ]

elements:

value |
value , elements

it seems not LL(1) to me. Clear cannot parse on "value"

Instinct