sdf-feature.cddl

start = sdf-syntax

sdf-syntax = {
 ; info will be required in most process policies
 ? info: sdfinfo
 ? namespace: named<text>
 ? defaultNamespace: text
 ; Thing is a composition of objects that work together in some way
 ? sdfThing: named<thingqualities>
 ; Object is a set of Properties, Actions, and Events that together
 ; perform a particular function
 ? sdfObject: named<objectqualities>
 ; Includes Properties, Actions, and Events as well as sdfData
 paedataqualities
 * $$SDF-EXTENSION-TOP
 EXTENSION-POINT<"top-ext">
}

sdfinfo = {
 ? title: text
 ? description: text
 ? version: text
 ? copyright: text
 ? license: text
 ? modified: modified-date-time
 ? features: [
               * (any .feature "feature-name") ; EXTENSION-POINT
             ]
 optional-comment
 * $$SDF-EXTENSION-INFO
 EXTENSION-POINT<"info-ext">
}

; Shortcut for a map that gives names to instances of X
; (has keys of type text and values of type X)
named<X> = { * text => X }

; EXTENSION-POINT is only used in framework syntax
EXTENSION-POINT<f> = ( * (quality-name .feature f) => any )
quality-name = text .regexp "([a-z][a-z0-9]*:)?[a-z$][A-Za-z$0-9]*"

sdf-pointer = global / same-object / true
global = text .regexp ".*[:#].*" ; rough CURIE or JSON Pointer syntax
same-object = referenceable-name
referenceable-name = text .regexp "[^:#]*"

; per se no point in having an empty list, but used for sdfRequired
; in odmobject-multiple_axis_joystick.sdf.json
pointer-list = [* sdf-pointer]

optional-comment = (
 ? $comment: text       ; source code comments only, no semantics
)

commonqualities = (
 ? description: text    ; long text (no constraints)
 ? label: text          ; short text (no constraints); default to key
 optional-comment
 ? sdfRef: sdf-pointer
 ; applies to qualities of properties, of data:
 ? sdfRequired: pointer-list
)

arraydefinitionqualities = (
 ? "minItems" => uint
 ? "maxItems" => uint
)

paedataqualities = (
 ; Property represents the state of an instance of an object
 ? sdfProperty: named<propertyqualities>
 ; Action invokes an application layer verb associated with an object
 ? sdfAction: named<actionqualities>
 ; Event represents an occurrence of event associated with an object
 ? sdfEvent: named<eventqualities>
 ; Data represents a piece of information that can be the state of a
 ; property or a parameter to an action or a signal in an event
 ? sdfData: named<dataqualities>

)

; for building hierarchy
thingqualities = {
 commonqualities
 ? sdfObject: named<objectqualities>
 ? sdfThing: named<thingqualities>
 paedataqualities
 arraydefinitionqualities
 * $$SDF-EXTENSION-THING
 EXTENSION-POINT<"thing-ext">
}

; for single objects, or for arrays of objects
objectqualities = {
 commonqualities
 paedataqualities
 arraydefinitionqualities
 * $$SDF-EXTENSION-OBJECT
 EXTENSION-POINT<"object-ext">
}

parameter-list = dataqualities

actionqualities = {
 commonqualities
 ? sdfInputData: parameter-list   ; sdfRequiredInputData applies here
 ? sdfOutputData: parameter-list  ; sdfRequired applies here
 ; zero or more named data type definitions that might be used above
 ? sdfData: named<dataqualities>
 * $$SDF-EXTENSION-ACTION
 EXTENSION-POINT<"action-ext">
}

eventqualities = {
 commonqualities
 ? sdfOutputData: parameter-list  ; sdfRequired applies here
 ; zero or more named data type definitions that might be used above
 ? sdfData: named<dataqualities>
 * $$SDF-EXTENSION-EVENT
 EXTENSION-POINT<"event-ext">
}

sdftype-name = text .regexp "[a-z][-a-z0-9]*"       ; EXTENSION-POINT

dataqualities = {
 commonqualities
 jsonschema
 ? "unit" => text
 ? nullable: bool
 ? "sdfType" => "byte-string" / "unix-time"
            / $SDF-EXTENSION-SDFTYPE .within sdftype-name
            / (sdftype-name .feature "sdftype-ext") ; EXTENSION-POINT
 ? contentFormat: text
 * $$SDF-EXTENSION-DATA
 EXTENSION-POINT<"data-ext">
}

propertyqualities = {
 ? observable: bool
 ? readable: bool
 ? writable: bool
 ~dataqualities
}

allowed-types = number / text / bool / null
              / [* number] / [* text] / [* bool]
              / {* text => any}
              / $SDF-EXTENSION-ALLOWED
              / (any .feature "allowed-ext")        ; EXTENSION-POINT

compound-type = (
  "type" => "object"
  ? required: [+text]
  ? properties: named<dataqualities>
)

optional-choice = (
 ? (("sdfChoice" => named<dataqualities>)
  // ("enum" => [+ text])) ; limited to text strings
)

jsonschema = (
 ? (("type" => "number" / "string" / "boolean" / "integer" / "array")
    // compound-type
    // $$SDF-EXTENSION-TYPE
    // (type: text .feature "type-ext")             ; EXTENSION-POINT
   )
 ; if present, all other qualities apply to all choices:
 optional-choice
 ; the next three should validate against type:
 ? const: allowed-types
 ? default: allowed-types
 ; number/integer constraints
 ? minimum: number
 ? maximum: number
 ? exclusiveMinimum: number
 ? exclusiveMaximum: number
 ? multipleOf: number
 ; text string constraints
 ? minLength: uint
 ? maxLength: uint
 ? pattern: text                ; regexp
 ? format: "date-time" / "date" / "time"
           / "uri" / "uri-reference" / "uuid"
           / $SDF-EXTENSION-FORMAT .within text
           / (text .feature "format-ext")           ; EXTENSION-POINT
 ; array constraints
 ? minItems: uint
 ? maxItems: uint
 ? uniqueItems: bool
 ? items: jso-items
)

jso-items = {
     ? sdfRef: sdf-pointer ; import limited to subset allowed here...
     ? description: text   ; long text (no constraints)
     optional-comment
     ; leave commonqualities out for non-complex data types,
     ; but need the above three.
     ; no further nesting: no "array"
     ? ((type: "number" / "string" / "boolean" / "integer")
        // compound-type
        // $$SDF-EXTENSION-ITEMTYPE
        // (type: text .feature "itemtype-ext")     ; EXTENSION-POINT
       )
     ; if present, all other qualities apply to all choices
     optional-choice
     ; jso subset
     ? minimum: number
     ? maximum: number
     ? format: text
     ? minLength: uint
     ? maxLength: uint
     * $$SDF-EXTENSION-ITEMS
     EXTENSION-POINT<"items-ext">
   }

modified-date-time = text .abnf modified-dt-abnf
modified-dt-abnf = "modified-dt" .det rfc3339z

; RFC 3339 sans time-numoffset, slightly condensed
rfc3339z = '
   date-fullyear   = 4DIGIT
   date-month      = 2DIGIT  ; 01-12
   date-mday       = 2DIGIT  ; 01-28, 01-29, 01-30, 01-31 based on
                             ; month/year
   time-hour       = 2DIGIT  ; 00-23
   time-minute     = 2DIGIT  ; 00-59
   time-second     = 2DIGIT  ; 00-58, 00-59, 00-60 based on leap sec
                             ; rules
   time-secfrac    = "." 1*DIGIT
   DIGIT           =  %x30-39 ; 0-9

   partial-time    = time-hour ":" time-minute ":" time-second
                     [time-secfrac]
   full-date       = date-fullyear "-" date-month "-" date-mday

   modified-dt     = full-date ["T" partial-time "Z"]
'