ngn-apl VS json

Some APL environments such as ngn/apl[0] allow tab completion like |o results in ⌽. This is probably available on tryapl.org too, but I can't test it when it's down :/

[0]: https://github.com/abrudz/ngn-apl

An example is the 40 line JSON::Tiny::Grammar of the Raku module JSON::Tiny. Raku grammars are analytical grammars. This one corresponds to the grammar of JSON defined by "RFC7159, which is a superset of ECMA-404, in that it permits any value as a top-level JSON string, not just arrays and objects".

For example, the JSON::Tiny grammar uses no backtracking, has almost entirely declarative rules, but leans on the default Turing complete powered top down recursive descent invocation of those rules to drive its predictive parsing.

A `rule` is a `token` with `:sigspace` also enabled (whitespace becomes the same as a call to `<.ws>`).

The only one of those that really looks anything like traditional regexes is the `value:sym` token. (Raku replaced non capturing grouping `(?:…)` with `[…]`, and character classes `[eE]` with `<[eE]>`)

This code was copied from https://github.com/moritz/json/blob/master/lib/JSON/Tiny/Gra... but some parts were simplified to be slightly easier to understand. Mainly I removed the Unicode handling capabilities.

It will generate a tree based structure when you use it.

    my $json = Q:to/END/;

For JSON specifically, here's a simple serializer/deserializer (Grammar, Actions).