schema.json

{
	"title": "Systems Schema",
	"description": "A validation schema for systems.json",
	"type": "object",
	"required": true,
	"additionalProperties": false,
	"properties": {
		"systems": {
			"description": "A set of different systems of units in the form of a flattened tree",
			"type": "object",
			"required": true,
			"additionalProperties": false,
			"patternProperties": {
				".+": {
					"type": "object",
					"additionalProperties": false,
					"properties": {
						"name": {
							"description": "A formal name for the unit system",
							"type": "string",
							"minLength": 1,
							"required": true
						},
						"inherits": {
							"description": "The key of the system it inherits from, if any",
							"type": "string",
							"minLength": 1,
							"required": false
						},
						"category": {
							"description": "True if a category of systems and not a system in its own right, else false. Defaults to false",
							"type": "boolean",
							"required": false
						},
						"historical": {
							"description": "True if the unit system is not in current usage, else false",
							"type": "boolean",
							"required": false
						},
						"notes": {
							"description": "Addtional notes as required",
							"type": "string",
							"required": false
						}
					}
				}
			}
		},
		"dimensions": {
			"description": "A set of types of recognized physical dimensions that can be measured",
			"type": "object",
			"required": true,
			"additionalProperties": false,
			"patternProperties": {
				".+": {
					"type": "object",
					"additionalProperties": false,
					"properties": {
						"name": {
							"description": "The common name of the dimension",
							"type": "string",
							"minLength": 1,
							"required": true
						},
						"otherNames": {
							"description": "Other names that are used to describe the dimension",
							"type": "array",
							"required": false,
							"uniqueItems": true,
							"items": {
								"type": "string"
							}
						},
						"symbol": {
							"description": "The standard symbol of the dimension",
							"type": "string",
							"minLength": 1,
							"required": true
						},
						"otherSymbols": {
							"description": "Other symbols that are used to signify the dimension",
							"type": "array",
							"required": false,
							"uniqueItems": true,
							"items": {
								"type": "string"
							}
						},
						"baseUnit": {
							"description": "The key of the unit that is other units can convert to/from",
							"type": "string",
							"minLength": 1,
							"required": true
						},
						"derived": {
							"description": "Describes how this dimension is derived from base dimensions. Multiple dimensions or a placeholder ('1') may be used, separated my * (multiplication) or / (division) symbols",
							"type": "string",
							"required": false
						},
						"dimensionless": {
							"description": "True if the dimension is dimensionless, else false. Defaults to false.",
							"type": "boolean",
							"required": false
						},
						"vector": {
							"description": "True if the dimension should be represented as a vector, else false if it should be a scalar",
							"type": "boolean",
							"required": true
						},
						"notes": {
							"description": "Additional notes as required",
							"type": "string",
							"required": false
						},
						"inheritedUnits": {
							"description": "The name of another dimension to inherit the units from.",
							"type": "string",
							"required": false
						},
						"units": {
							"description": "A set of units that can be used to describe the dimension",
							"type": "object",
							"required": true,
							"additionalProperties": false,
							"patternProperties": {
								".+": {
									"type": "object",
									"required": true,
									"additionalProperties": false,
									"properties": {
										"name": {
											"description": "The standard name of the unit",
											"type": "string",
											"minLength": 1,
											"required": true
										},
										"plural": {
											"description": "The plural form of the standard name of the unit",
											"type": "string",
											"minLength": 1,
											"required": false
										},
										"otherNames": {
											"description": "A set of other names that the unit is known by",
											"type": "array",
											"required": false,
											"uniqueItems": true,
											"items": {
												"type": "string"
											}
										},
										"symbol": {
											"description": "The standard symbol of the dimension. Only optional if unit does not have a symbol",
											"type": "string",
											"minLength": 1,
											"required": false
										},
										"otherSymbols": {
											"description": "Other symbols used to signify the unit",
											"type": "array",
											"required": false,
											"uniqueItems": true,
											"items": {
												"type": "string"
											}
										},
										"symbolFirst": {
											"description": "Determines if the symbol should appear before the value. Defaults to false",
											"type": "boolean",
											"required": false
										},
										"type": {
											"description": "An enum describing the type of a unit and how it should be treated. range, fractional, whole may be added later",
											"type": "string",
											"required": true,
											"enum": ["customary", "si", "binary"]
										},
										"systems": {
											"description": "A set of unit systems that use this unit",
											"type": "array",
											"required": true,
											"uniqueItems": true,
											"description": "required needs to be set to true!",
											"items": {
												"type": "string"
											}
										},
										"excludedSystems": {
											"description": "A set of unit systems that are not allowed to use this unit. Useful for excluding specific systems classified lower in the system tree",
											"type": "array",
											"required": false,
											"uniqueItems": true,
											"items": {
												"type": "string"
											}
										},
										"tags": {
											"description": "A set of tags to describe additional properties of a unit",
											"type": "array",
											"required": false,
											"uniqueItems": true,
											"items": {
												"type": "string",
												"enum": ["dry-only", "fluid-only", "cooking"]
											}
										},
										"multiplier": {
											"description": "A scale factor to multiply by when converting from the base unit to this unit. Default is 1",
											"type": "number",
											"required": false
										},
										"uncertainty": {
											"description": "The absolute uncertainty within a conversion between this unit and the base unit.",
											"type": "number",
											"required": false
										},
										"offset": {
											"description": "A constant offset to add when converting from base unit to this unit",
											"type": "number",
											"required": false
										},
										"estimation": {
											"description": "True if the multiplier and/or offset are estimated or not exact",
											"type": "boolean",
											"required": false
										},
										"rare": {
											"description": "True if the unit rarely used within the unit systems it is part of, else false. Defaults to false",
											"type": "boolean",
											"required": false
										},
										"acceptedPrefixes": {
											"description": "A set of the names of acceptable prefixes to apply to this unit",
											"type": "array",
											"required": false,
											"uniqueItems": true,
											"items": {
												"type": "string"
											}
										},
										"excludedPrefixes": {
											"description": "A set of names of unacceptable prefixes to apply to this unit",
											"type": "array",
											"required": false,
											"uniqueItems": true,
											"items": {
												"type": "string"
											}
										},
										"prefixName": {
											"description": "The prefix already applied to this unit.",
											"type": "string",
											"required": false
										},
										"prefixFreeName": {
											"description": "The name of the unit without prefix applied.",
											"type": "string",
											"required": false
										},
										"notes": {
											"description": "Additional notes as required",
											"type": "string",
											"required": false
										}
									}
								}
							}
						}
					}
				}
			}
		},
		"prefixes": {
			"type": "object",
			"required": true,
			"additionalProperties": false,
			"patternProperties": {
				".+": {
					"type": "object",
					"additionalProperties": false,
					"properties": {
						"symbol": {
							"type": "string",
							"required": true
						},
						"type": {
							"type": "string",
							"enum": ["si", "siBinary", "siUnofficial"],
							"required": true
						},
						"base": {
							"type": "number",
							"required": false
						},
						"power": {
							"type": "number",
							"required": false
						},
						"multiplier": {
							"type": "number",
							"required": false
						},
						"rare": {
							"type": "boolean",
							"required": false
						},
						"notes": {
							"type": "string",
							"required": false
						}
					}
				}
			}
		}
	}
}