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|
=================================
Interoperability with other tools
=================================
JSON Schema
-----------
ATD type definitions can be translated to
`JSON Schema <https://json-schema.org/>`_
with ``atdcat``. The user must specify the main type on the command
line since ATD doesn't have a notion of main type or root type.
This can be useful for target languages that are not yet supported by
ATD or for educational purposes.
Example
^^^^^^^
Input: ATD file ``message.atd``::
type msg = {
subject: string;
?body: string option;
~attachments: attachment list;
}
type attachment = [
| Image of string
| Virus
]
Conversion to JSON Schema::
$ atdcat -jsonschema msg message.atd -o message.schema.json
Output: JSON Schema file ``message.schema.json``::
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"description": "Translated by atdcat from 'message.atd'",
"type": "object",
"required": [ "subject" ],
"properties": {
"subject": { "type": "string" },
"body": { "type": "string" },
"attachments": {
"type": "array",
"items": { "$ref": "#/definitions/attachment" }
}
},
"definitions": {
"attachment": {
"oneOf": [
{
"type": "array",
"minItems": 2,
"items": false,
"prefixItems": [ { "const": "Image" }, { "type": "string" } ]
},
{ "const": "Virus" }
]
}
}
}
The ``jsonschema`` tool (Python implementation) can validate JSON data
using the JSON Schema file that we generated. For example, passing an
empty object ``{}`` correctly results in an error telling us the ``subject``
field is missing::
$ jsonschema message.json -i <(echo '{}')
{}: 'subject' is a required property
With valid JSON input such as
``{"subject": "hello", "attachments": ["Virus"]}``, the command
exits successfully and silently::
$ jsonschema message.json -i <(echo '{"subject": "hello", "attachments": ["Virus"]}')
|
