schema.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "JSON S-expression Language Schema",
  "description": "Schema for a custom JSON S-expression language.",
  "definitions": {
    "ref": {
      "title": "Reference Operator",
      "description": "A reference to a function or identifier.",
      "type": "array",
      "minItems": 2,
      "maxItems": 2,
      "items": [
        { "enum": ["ref"], "title": "Operator", "description": "The operator type, representing a reference to a function or identifier." },
        { "type": "string", "title": "Identifier", "description": "The identifier or function name." }
      ]
    },
    "call": {
      "title": "Call Operator",
      "description": "A function call.",
      "type": "array",
      "minItems": 2,
      "maxItems": 3,
      "items": [
        { "const": "call", "title": "Operator", "description": "The operator type, representing a function call." },
        { "$ref": "#/definitions/ref", "title": "Reference", "description": "The reference to a function or identifier." },
        {
          "type": "array",
          "items": {
            "$ref": "#"
          },
          "title": "Arguments",
          "description": "The arguments passed to the function."
        }
      ]
    }
  },
  "oneOf": [
    { "$ref": "#/definitions/ref" },
    { "$ref": "#/definitions/call" },
    { "type": "number", "title": "Number", "description": "A JSON number." },
    { "type": "string", "title": "String", "description": "A JSON string." },
    { "type": "boolean", "title": "Boolean", "description": "A JSON boolean." },
    { "type": "null", "title": "Null", "description": "A JSON null value." },
    {
      "title": "Object",
      "description": "A generic JSON object with additional properties.",
      "type": "object",
      "additionalProperties": {
        "$ref": "#"
      }
    }
  ]
}