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FlatJSON

JSON Flattening Parser and Stringifier in Scratch.

Open with TurboWarp editor:
https://turbowarp.org/editor?project_title=FlatJSON&project_url=bddjr.github.io/FlatJSON/FlatJSON.sb3

Download sb3 file:
https://bddjr.github.io/FlatJSON/FlatJSON.sb3

Scratch Project Link:
https://scratch.mit.edu/projects/1384506526/

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Rules

JSON syntax reference: https://www.json.org/json-en.html

Scratch converts strings to lowercase before comparison, so it is more lenient than the JSON specification syntax:
In input strings, the letter immediately following \ can be uppercase (for example \N), and the true, false, and null keywords can use uppercase letters (TRUE, FALSE, NULL).
The output will automatically convert them to lowercase, ensuring compliance with JSON syntax (except for the rawjson type).

key:

• An empty key represents the root; non-empty keys must start with /.
• Multi-level keys are separated by /, for example /a/b/c.
• / will be escaped as \/, and \ will be escaped as \\.
• If a character is a control character (U+0000 - U+001F), use the escaped format, for example \b\t\n\f\r\u001f.
• It is recommended not to use uppercase letters, because Scratch converts strings to lowercase before comparison.

type:

• object
• array
• string
• number
• boolean
• null
• rawjson (stringify only)

value:

• When the type is array, the value is used to store the length of the array.
• \b will be parsed as � (U+FFFD), because scratch-parser removes all \b in a Scratch project's project.json.
  Older versions of scratch-parser would even turn "\\b" into "\", causing project loading to fail.

The returned error is in item 1 of FlatJSON.error.
If this item exists, the returned data is invalid.
If this item does not exist, no error occurred.

Variables, lists, and custom blocks starting with FlatJSON/internal. are for internal use by FlatJSON.
Do not call or modify them unless you know what you are doing.

Do not execute multiple FlatJSON custom blocks in parallel within the same sprite.
If needed, please use clones.

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Parse

Custom block: FlatJSON.parse

Input variable:

• FlatJSON.parse.input
  The JSON to be parsed.

Output lists:

• FlatJSON.parse.output.key
  The key list, formatted as described in "Rules".
• FlatJSON.parse.output.key.basename
  The basename list of the keys, for example, the basename in /a/b/c is c.
• FlatJSON.parse.output.key.parent
  The parent key list, for example, the parent key of /a/b/c is /a/b.
  The parent key of an empty key is an empty key.
• FlatJSON.parse.output.key.prefix
  The prefix list of the keys, for example, the prefix in /a/b/c is /a/b/.
• FlatJSON.parse.output.type
  The type list, possible types are described in "Rules".
• FlatJSON.parse.output.value
  The value list.
  If the type is object or null, the value is an empty string.
  If the type is array, the value is the array length.

Errors:

• parse: Unexpected end of JSON input
• parse: Unexpected token '<char>' at position <offset>
• parse: Expected double-quoted property name in JSON at position <offset>
• parse: Bad control character in string literal in JSON at position <offset>
• parse: Bad escaped character in JSON at position <offset>
• parse: Bad Unicode escape in JSON at position <offset>
• parse: Expected ':' after property name in JSON at position <offset>
• parse: Expected ',' or '}' after property value in JSON at position <offset>
• parse: Expected ',' or ']' after array element in JSON at position <offset>
• parse: Unexpected number in JSON at position <offset>
• parse: Unexpected number '<number>' in JSON

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Stringify

Custom block: FlatJSON.stringify

Input variables:

• FlatJSON.stringify.input.root_key
  Specifies which root key to start stringifying from.
• FlatJSON.stringify.input.space
  Specifies the indentation string, for example, two spaces.

Input lists:

• FlatJSON.stringify.input.key
  The key list.
• FlatJSON.stringify.input.type
  The type list.
• FlatJSON.stringify.input.value
  The value list.

Output variable:

• FlatJSON.stringify.output
  The output JSON.

Errors:

• stringify: Expected input key, type, and value lists to have the same length
• stringify: Expected non-empty input
• stringify: Expected input key list to contain the root key
• stringify: Expected non-empty key to start with '/' at position <index>
• stringify: Unexpected end of key input at position <index>
• stringify: Bad escaped character of key input at position <index>:<offset>
• stringify: Bad Unicode escape of key input at position <index>:<offset>
• stringify: Unexpected type '<type>' at position <index>

This block checks the FlatJSON.stringify.input.key list, and replaces each item in it with a normalized key.

This block checks whether the input number is valid, and turns it into null if invalid.

This block does not validate whether the input rawjson conforms to the JSON specification; you need to ensure the input JSON is valid yourself.

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copy_parse_output_to_stringify_input

Custom block: FlatJSON.copy_parse_output_to_stringify_input

This block performs the following operations:

• Copies FlatJSON.parse.output.key to FlatJSON.stringify.input.key
• Copies FlatJSON.parse.output.type to FlatJSON.stringify.input.type
• Copies FlatJSON.parse.output.value to FlatJSON.stringify.input.value

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clear

Custom block: FlatJSON.clear

Clears FlatJSON.error, then automatically calls the following custom blocks:

• FlatJSON.clear_temporary_variables
• FlatJSON.clear_parse_input
• FlatJSON.clear_parse_output
• FlatJSON.clear_stringify_input
• FlatJSON.clear_stringify_output

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clear_temporary_variables

Custom block: FlatJSON.clear_temporary_variables

Clears all variables and lists starting with FlatJSON/internal.temp..

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clear_parse_input

Custom block: FlatJSON.clear_parse_input

Clears the FlatJSON.parse.input variable.

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clear_parse_output

Custom block: FlatJSON.clear_parse_output

Clears all lists starting with FlatJSON.parse.output..

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clear_stringify_input

Custom block: FlatJSON.clear_stringify_input

Clears all variables and lists starting with FlatJSON.stringify.input..

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clear_stringify_input_lists

Custom block: FlatJSON.clear_stringify_input_lists

Clears all lists starting with FlatJSON.stringify.input..

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clear_stringify_output

Custom block: FlatJSON.clear_stringify_output

Clears the FlatJSON.stringify.output variable.

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License

This project is released into the public domain under the Unlicense.

The "Scratch" name is a trademark of the Scratch Foundation.