refactor: Improve validation of GUI elements and GUI attributes (DEV-1082)

docs/02-knora-ontologies/salsah-gui.md

@@ -18,202 +18,192 @@ brevity, we omit the prefix in this document.
 
 ## Properties
 
-`guiOrder`
+### guiOrder
+
+`guiOrder` can be attached to an `owl:Restriction` representing a cardinality
+in a resource class, to indicate the order in which properties
+should be displayed in the GUI. The object is a non-negative
+integer. For example, a property with `guiOrder` 0 would be
+displayed first, followed by a property with `guiOrder` 1, and so
+on.
 
-:   Can be attached to an `owl:Restriction` representing a cardinality
-    in a resource class, to indicate the order in which properties
-    should be displayed in the GUI. The object is a non-negative
-    integer. For example, a property with `guiOrder` 0 would be
-    displayed first, followed by a property with `guiOrder` 1, and so
-    on.
+### guiElement
 
-`guiElement`
+`guiElement` can be attached to a property definition to indicate which SALSAH
+GUI element should be used to enter data for the property. This
+should be one of the individuals of class `Guielement` described
+below.
 
-:   Can be attached to a property definition to indicate which SALSAH
-    GUI element should be used to enter data for the property. This
-    should be one of the individuals of class `Guielement` described
-    below.
+### guiAttribute
 
-`guiAttribute`
-
-:   Can be attached to a property definition to provide attributes for
-    the GUI element specified in `guiElement`. The objects of this
-    predicate are written in a DSL with the following syntax:
+`guiAttribute` can be attached to a property definition to provide attributes for
+the GUI element specified in `guiElement`. The objects of this
+predicate are written in a DSL with the following syntax:
 
 ```ebnf
-object = attribute name, "=", attribute value ;
-
-attribute name = identifier ;
-
-identifier = letter , { letter } ;
-
-attribute value = integer | decimal | percent | string | iri ;
-
-percent = integer, "%" ;
-
-iri = "<", string, ">" ;
+object              = attribute name, "=", attribute value ;
+attribute name      = identifier ;
+identifier          = letter , { letter } ;
+attribute value     = integer | decimal | percent | string | iri ;
+percent             = integer, "%" ;
+iri                 = "<", string, ">" ;
 ```
 
 The attributes used with each GUI element are described below under
 [Individuals](#individuals).
 
-`guiAttributeDefinition`
+### guiAttributeDefinition
 
-:   Used only in the `salsah-gui` ontology itself, as a predicate
-    attached to instances of `Guielement` (see [Individuals](#individuals)),
-    to specify the attributes that can be given as objects of `guiAttribute` when a given
-    `Guielement`. is used. The objects of this predicate are written in
-    a DSL with the following syntax:
+`guiAttributeDefinition` is used only in the `salsah-gui` ontology itself, as a predicate
+attached to instances of `Guielement` (see [Individuals](#individuals)),
+to specify the attributes that can be given as objects of `guiAttribute` when a given
+`Guielement` is used. The objects of this predicate are written in
+a DSL with the following syntax:
 
 ```ebnf
-object = attribute name, [ "(required)" ], ":", attribute type, [ enumerated values ] ;
-
-enumerated values = "(", enumerated value, { "|", enumerated value } ")" ;
-
-attribute name = identifier ;
-
-attribute type = "integer" | "decimal" | "percent" | "string" | "iri" ;
-
-enumerated value = identifier ;
-
-identifier = letter , { letter } ;
+object              = attribute name, [ "(required)" ], ":", attribute type, [ enumerated values ] ;
+enumerated values   = "(", enumerated value, { "|", enumerated value } ")" ;
+attribute name      = identifier ;
+attribute type      = "integer" | "decimal" | "percent" | "string" | "iri" ;
+enumerated value    = identifier ;
+identifier          = letter , { letter } ;
 ```
 
-    Enumerated values are allowed only if `attribute type` is `string`.
-    If enumerated values are provided for an attribute, the attribute
-    value given via `guiAttribute` must be one of the enumerated values.
+Enumerated values are allowed only if `attribute type` is `string`.
+If enumerated values are provided for an attribute, the attribute
+value given via `guiAttribute` must be one of the enumerated values.
 
 ## Classes
 
-`Guielement`
+### Guielement
 
-:   The instances of this class are individuals representing SALSAH GUI
-    elements for data entry.
+The instances of class `Guielement` are individuals representing SALSAH GUI
+elements for data entry.
 
 ## Individuals
 
-`Colorpicker`
+### Colorpicker
 
-:   A GUI element for selecting a color. A property definition that uses
-    this element may also contain a `guiAttribute` predicate whose
-    object is a string in the form `"ncolors=N"`, where `N` is an
-    integer specifying the number of colors to display.
+`Colorpicker` is a GUI element for selecting a color. A property definition that uses
+this element may also contain a `guiAttribute` predicate whose
+object is a string in the form `"ncolors=N"`, where `N` is an
+integer specifying the number of colors to display.
 
-`Date`
+### Date
 
-:   A GUI element for selecting a date.
+`Date` is a GUI element for selecting a date.
 
-`Geometry`
+### Geometry
 
-:   A GUI element for selecting the geometry of a two-dimensional
-    region.
+`Geometry` is a GUI element for selecting the geometry of a two-dimensional
+region.
 
-`Geonames`
+### Geonames
 
-:   A GUI element for selecting a [Geonames](http://www.geonames.org/)
-    identifier.
+`Geonames` is a GUI element for selecting a [Geonames](http://www.geonames.org/)
+identifier.
 
-`Interval`
+### Interval
 
-:   A GUI element for selecting a time interval in an audio or video
-    recording.
+`Interval` is a GUI element for selecting a time interval in an audio or video
+recording.
 
-`List`
+### List
 
-:   A GUI element for selecting an item in a hierarchical list (see
-    [ListValue](knora-base.md#listvalue)). A property definition that
-    uses this element must also contain this `guiAttribute` predicate:
+`List` is a GUI element for selecting an item in a hierarchical list (see
+[ListValue](knora-base.md#listvalue)). A property definition that
+uses this element must also contain this `guiAttribute` predicate: 
 
-    -   `"hlist=<LIST_IRI>"`, where `LIST_IRI` is the IRI of a
-        `knora-base:ListNode` that is the root node of a hierarchical list.
+- `"hlist=<LIST_IRI>"`, where `LIST_IRI` is the IRI of a
+`knora-base:ListNode` that is the root node of a hierarchical list.
 
-`Pulldown`
+### Pulldown
 
-:   A GUI element for selecting an item in a flat list (see
-    [ListValue](knora-base.md#listvalue)) using a pull-down menu. A
-    property definition that uses this element must also contain this
-    `guiAttribute` predicate:
+`Pulldown` is a GUI element for selecting an item in a flat list (see
+[ListValue](knora-base.md#listvalue)) using a pull-down menu. A
+property definition that uses this element must also contain this
+`guiAttribute` predicate: 
 
-    -   `"hlist=<LIST_IRI>"`, where `LIST_IRI` is the IRI of a
-        `knora-base:ListNode` that is the root node of a hierarchical list.
+- `"hlist=<LIST_IRI>"`, where `LIST_IRI` is the IRI of a
+`knora-base:ListNode` that is the root node of a hierarchical list.
 
-`Radio`
+### Radio
 
-:   A GUI element for selecting an item in a flat list (see
-    [ListValue](knora-base.md#listvalue)) using radio buttons. A property
-    definition that uses this element must also contain this
-    `guiAttribute` predicate:
+`Radio` is a GUI element for selecting an item in a flat list (see
+[ListValue](knora-base.md#listvalue)) using radio buttons. A property
+definition that uses this element must also contain this
+`guiAttribute` predicate:
 
-    -   `"hlist=<LIST_IRI>"`, where `LIST_IRI` is the IRI of a
-        `knora-base:ListNode` that is the root node of a hierarchical list.
+- `"hlist=<LIST_IRI>"`, where `LIST_IRI` is the IRI of a
+`knora-base:ListNode` that is the root node of a hierarchical list.
 
-`Richtext`
+### Richtext
 
-:   A GUI element for editing multi-line formatted text.
+`Richtext` is a GUI element for editing multi-line formatted text.
 
-`Searchbox`
+### Searchbox
 
-:   A GUI element for searching for a resource by matching text in its
-    `rdfs:label`. For DSP-API v1, a property definition that uses this
-    element may also contain this `guiAttribute` predicate:
+`Searchbox` is a GUI element for searching for a resource by matching text in its
+`rdfs:label`. For DSP-API v1, a property definition that uses this
+element may also contain this `guiAttribute` predicate:
 
-    -   `"numprops=N"`, where `N` is an integer specifying the number of
-        describing properties to be returned for each found resource.
+-   `"numprops=N"`, where `N` is an integer specifying the number of
+describing properties to be returned for each found resource.
 
-    For DSP-API v2, the `guiAttribute` has no effect.
+For DSP-API v2, the `guiAttribute` has no effect.
 
-`SimpleText`
+### SimpleText
 
-:   A GUI element for editing a single line of unformatted text. A
-    property definition that uses this element may also contain a
-    `guiAttribute` predicate with one or both of the following objects:
+`SimpleText` is a GUI element for editing a single line of unformatted text. A
+property definition that uses this element may also contain a
+`guiAttribute` predicate with one or both of the following objects:
 
-    -   `"size=N"`, where `N` is an integer specifying the size of the
-        text field.
-    -   `"maxlength=N"`, where `N` is an integer specifying the maximum
-        length of the string to be input.
+-   `"size=N"`, where `N` is an integer specifying the size of the
+text field.
+-   `"maxlength=N"`, where `N` is an integer specifying the maximum
+length of the string to be input.
 
-`Slider`
+### Slider
 
-:   A GUI element for choosing numerical values using a slider. A
-    property definition that uses this element must also contain a
-    `guiAttribute` predicate with both of the following objects:
+`Slider` is a GUI element for choosing numerical values using a slider. A
+property definition that uses this element must also contain a
+`guiAttribute` predicate with both of the following objects:
 
-    -   `"min=N"`, where `N` is an integer specifying the minimum value
-        of the input.
-    -   `"max=N"`, where `N` is an integer specifying the maximum value
-        of the input.
+-   `"min=N"`, where `N` is an integer specifying the minimum value
+of the input.
+-   `"max=N"`, where `N` is an integer specifying the maximum value 
+of the input.
 
-`Spinbox`
+### Spinbox
 
-:   A GUI element for choosing numerical values using a spinbox. A
-    property definition that uses this element may also contain a
-    `guiAttribute` predicate with one or both of the following objects:
+`Spinbox` is a GUI element for choosing numerical values using a spinbox. A
+property definition that uses this element may also contain a
+`guiAttribute` predicate with one or both of the following objects:
 
-    -   `"min=N"`, where `N` is an integer specifying the minimum value
-        of the input.
-    -   `"max=N"`, where `N` is an integer specifying the maximum value
-        of the input.
+-   `"min=N"`, where `N` is an integer specifying the minimum value
+of the input.
+-   `"max=N"`, where `N` is an integer specifying the maximum value
+of the input.
 
-`Textarea`
+### Textarea
 
-:   A GUI element for editing multi-line unformatted text. A property
-    definition that uses this element may also contain a `guiAttribute`
-    predicate with one or more of the following objects:
+`Textarea` is a GUI element for editing multi-line unformatted text. A property
+definition that uses this element may also contain a `guiAttribute`
+predicate with one or more of the following objects:
 
-    -   `"width=N"`, where `N` is a percentage of the window width (an
-        integer followed by `%`).
-    -   `"cols=N"`, where `N` is an integer representing the number of
-        colums in the text entry box.
-    -   `"rows=N"`, where `N` is an integer specifying the height of the
-        text entry box in rows.
-    -   `"wrap=W"`, where `W` is `soft` or `hard` (see
-        [wrap](https://www.w3.org/TR/html5/sec-forms.html#element-attrdef-textarea-wrap)).
+-   `"width=N"`, where `N` is a percentage of the window width (an
+integer followed by `%`).
+-   `"cols=N"`, where `N` is an integer representing the number of
+colums in the text entry box.
+-   `"rows=N"`, where `N` is an integer specifying the height of the
+text entry box in rows.
+-   `"wrap=W"`, where `W` is `soft` or `hard` (see
+[wrap](https://www.w3.org/TR/html5/sec-forms.html#element-attrdef-textarea-wrap)).
 
-`Checkbox`
+### Checkbox
 
-:   A GUI element for choosing a boolean value using a checkbox.
+`Checkbox` is a GUI element for choosing a boolean value using a checkbox.
 
-`Fileupload`
+### Fileupload
 
-:   A GUI element for uploading a file.
+`Fileupload` is a GUI element for uploading a file.