para

use v6.e.PREVIEW;

use Qwiratry::DatabaseStorage::Location::Tree;
use Qwiratry::Mold::Slang;
use Qwiratry::Transformer;
use X::Qwiratry;

# §8 default merge Transformer (plan Q18 / §16.4.5): rebuild document from
# $*CONTEXT<rows>. Nested tables override :transformer on useTable.
transformer LocationJSONDefaultMerge {
	mold TOP
		when { True }
		do {
			# Push (not .Array on a Seq of Hashes): Hash is Iterable, so
			# `$seq.Array` / `[ $seq ]` flatten or nest wrongly.
			my @out;
			@out.push(%($_)) for @($*CONTEXT<rows> // []);
			@out
		}
}



Qwiratry *::DatabaseStorage::Location::JSON — JSON document ↔ rows


NAME

Qwiratry *::DatabaseStorage::Location::JSON


TITLE

Location-backed tables whose documents are JSON arrays of objects


SUBTITLE

AUTHOR

Ships with the C<Qwiratry::Format::JSON> distribution (not core). Thin
subclass of core C<Qwiratry::DatabaseStorage::Location::Tree> that defaults
C<:format('JSON')> and advertises today's root/identity/object-key projection
as §8 Format defaults (plan DatabaseStorage-Location-Tree §8 / Q4 / Q14).


item

Override C<:table-selector> / C<:row-selector> / C<:field-projection> /
C<:transformer> / C<:path-transformer> on C<useTable> (or the constructor)
for nested tables. Default C<:path-transformer> is core
C<associative-path-transformer> (plan §10.3 / §16.4.3).


code

=begin code

use Qwiratry::TaOP;
use Qwiratry::Mold::Slang;
use Qwiratry::DatabaseStorage::Location::JSON;  # or rely on Database load-library

my $db = Database.new(
	storage-type => 'Location::JSON',
	location => './data',
);
my $t = $db.useTable(name => 'people', action => 'can-create');
$t.add-row({ name => 'Ada', age => 36 });
$t.storage-object.flush;  # Tree sync is explicit (plan Q20)
# → ./data/people.json

# Nested table under a key (override §8 defaults; keep sibling structure).
# Merge mold sees $*CONTEXT<rows> (plan Q18); topic is the document.
clear-collected-molds();
transformer MergePeople {
	mold TOP
		when { True }
		do {
			my %out = $_ ~~ Associative ?? %($_) !! %();
			%out<people> = [@($*CONTEXT<rows> // []).map({ %($_) })];
			%out
		}
}
# my $roster = $db.useTable(
#	name => 'roster',
#	action => 'use',
#	row-selector => sub (Mu $doc) { slip(($doc<people> // []).list) },
#	transformer => MergePeople.new,
# );

=end code


See also C<t/03-location-json.rakutest> and the core Qwiratry plan
C<docs/rakudoc/Developing/DatabaseStorage-Location-Tree.md>.



class Qwiratry::DatabaseStorage::Location::JSON
	is Qwiratry::DatabaseStorage::Location::Tree
{
	# Parent Location defaults C<format> to C<JSONdemo>; this Format dist
	# wants C<JSON>. Keep a thin C<new> so an omitted C<:format> becomes
	# C<JSON> without treating an explicit C<JSONdemo> as "unset".
	method new(:$format = 'JSON', *%rest) {
		callwith(|%rest, :$format);
	}

	# §8 defaults when the caller/constructor did not supply a stage.
	# Callables: multi-node results use C<slip>; a bare Array/Hash is one node.
	# Parent attrs are private to Tree — set via C<is rw> accessors.
	submethod TWEAK() {
		unless self.table-selector.defined {
			self.table-selector = sub (Mu $document) { $document };
		}

		# Anonymous C<sub> (not C<< -> >>) so C<return> / C<slip> work.
		unless self.row-selector.defined {
			self.row-selector = sub (Mu $table-root) {
				without $table-root {
					return slip();
				}
				if $table-root ~~ Positional
					&& $table-root !~~ Str
					&& $table-root !~~ Associative
				{
					return slip($table-root.list);
				}
				if $table-root ~~ Associative {
					return $table-root;
				}
				X::Qwiratry::DatabaseStorage::UnexpectedShape.new(
					message => 'JSON default row-selector expected array or object table root',
					stage => 'row-selector',
					got => $table-root,
				).throw;
			};
		}

		unless self.field-projection.defined {
			self.field-projection = sub (Mu $row-node) {
				$row-node ~~ Associative
					?? %($row-node)
					!! X::Qwiratry::DatabaseStorage::UnexpectedShape.new(
						message => 'JSON default field-projection expected object row',
						stage => 'field-projection',
						got => $row-node,
					).throw;
			};
		}

		# Default merge: slang Transformer above (plan Q18 / §16.4.5).
		# Nested tables override :transformer (Callable still accepted).
		unless self.transformer.defined {
			self.transformer = LocationJSONDefaultMerge.new;
		}

		# §10.3: EMPTY mold — ancestors {}, table-site / row-collection [].
		unless self.path-transformer.defined {
			self.path-transformer = self.associative-path-transformer;
		}
	}
}


root

Qwiratry::Format::JSON

User-visible changes by release


Qwiratry::Format::JSON — Changelog

React

=begin React :component<HeaderCol> :id<menu> 
=para L<Documentation|/doc/introduction>
=para L<Modules| /mods>
=para L<Examples| file:../examples/index.podlite>
=para L<AI|file:../mcp/index.podlite>
=para L<Download |file:../download/index.podlite>
=para L<About|file:../about/index.podlite>
=para 🔍 K<⌘K>/K<ctrl-K>
=end React


=begin React :component<HeaderCol> :id<footer>  
=begin nested :!nested
=item1 B<Language>
    =item2 L<Get started|file:../getting-started/getting-started.podlite>
    =item2 L<Why Raku?|/doc/language/faq#Why-should-I-learn-Raku-What's-so-great-about-it>
    =item2 L<Try Raku|https://glot.io/new/raku>
    =item2 L<Download | file:../download/index.podlite>
    =item2 L<Raku cheat sheet|https://github.com/Raku/mu/blob/master/docs/Perl6/Cheatsheet/cheatsheet.txt>
    =item2 L<Raku on Exercism|https://exercism.org/tracks/raku>
    =item2 L<Wikipedia|https://en.wikipedia.org/wiki/Raku_(programming_language)>

=end nested
=begin nested :!nested

=item1 B<L<Documentation|/doc>>
    =item2 L<Getting started, Migration guides from other languages, & Tutorials | file:../doc/introduction.podlite>
    =item2 L<Language References|file:../doc/reference.podlite>
    =item2 L<Type Reference| file:../doc/types.podlite>
    =item2 L<Miscellaneous| file:../doc/miscellaneous.podlite>
    =item2 L<FAQs (Frequently Asked Questions)|/doc/language/faq>
    =item2 L<Community|/doc/language/community>
    =item2 L<The list of all documents|file:../doc/index.podlite>
    =item2 L<Hand these documents to an AI agent|file:../mcp/index.podlite>

=end nested
=begin nested :!nested
=item1 B<Learning>
    =item2 L<The Raku Guide|https://raku.guide/>
    =item2 L<Wikibook |https://en.wikibooks.org/wiki/Raku_Programming>
    =item2 L<Books |https://perl6book.com/>
    =item2 L<Rosetta Code | https://www.raku.org/community/rosettacode>
    =item2 L<Learn Raku in Y minutes|https://learnxinyminutes.com/docs/raku/>
    =item2 L<Golfing |https://github.com/AlexDaniel/raku-golf-cheatsheet>
=end nested
=begin nested :!nested

=item1 B<Explore>
    =item2 L<Raku Blog Aggregator|https://planet.raku.org/>
    =item2 L<Rakudo Weekly|https://rakudoweekly.blog/>
    =item2 L<The Weekly Challenge |https://perlweeklychallenge.org/>
    =item2 L<Raku Advent Calendar|https://raku-advent.blog/>

=end nested
=end React


Built with L<Podlite|https://podlite.org> — the markup and publishing tools behind this site.


=begin React :component<CookieConsent> :id<CookieConsent> :buttonCaption("Got it!")
=para
This website uses cookies for analytics.
=end React


Qwiratry *::DatabaseStorage::Location::JSON

NAME

AUTHOR

Qwiratry::Format::JSON v0.0.2

Authors

License

Dependencies

Test Dependencies

Provides

Documentation