akiym / json_fast

a naive imperative json parser in perl6, to evaluate performance against JSON::Tiny

JSON::Fast

a naive imperative json parser in pure perl6 (but with direct access to nqp:: ops), to evaluate performance against JSON::Tiny. It is a drop-in replacement for JSON::Tiny’s from-json and to-json subs, but it offers a few extra features.

Currently it seems to be about 4x faster and uses up about a quarter of the RAM JSON::Tiny would use.

This module also includes a very fast to-json function that tony-o created and lizmat later completely refactored.

Exported subroutines

to-json

    my $*JSON_NAN_INF_SUPPORT = 1; # allow NaN, Inf, and -Inf to be serialized.
    say to-json [<my Perl data structure>];
    say to-json [<my Perl data structure>], :!pretty;
    say to-json [<my Perl data structure>], :spacing(4);

enum Blerp <Hello Goodbye>;
say to-json [Hello, Goodbye]; # ["Hello", "Goodbye"]
say to-json [Hello, Goodbye], :enums-as-value; # [0, 1]

Encode a Perl data structure into JSON. Takes one positional argument, which is a thing you want to encode into JSON. Takes these optional named arguments:

pretty

Bool. Defaults to True. Specifies whether the output should be "pretty", human-readable JSON. When set to false, will output json in a single line.

spacing

Int. Defaults to 2. Applies only when pretty is True. Controls how much spacing there is between each nested level of the output.

sorted-keys

Bool, defaults to False. Specifies whether keys from objects should be sorted before serializing them to a string or if $obj.keys is good enough.

from-json

    my $x = from-json '["foo", "bar", {"ber": "bor"}]';
    say $x.perl;
    # outputs: $["foo", "bar", {:ber("bor")}]

Takes one positional argument that is coerced into a Str type and represents a JSON text to decode. Returns a Perl datastructure representing that JSON.

Additional features

Strings containing multiple json pieces

When the document contains additional non-whitespace after the first successfully parsed JSON object, JSON::Fast will throw the exception X::JSON::AdditionalContent. If you expect multiple objects, you can catch that exception, retrieve the parse result from its parsed attribute, and remove the first rest-position characters off of the string and restart parsing from there.