Hide Secret Messages In Plain Sight With Zero-Width Characters | Hackaday
UCS is a superset of all other character set standards. .. file with the character U +FEFF (ZERO WIDTH NO-BREAK SPACE), also known as the. If there is no displayable right-to-left character in a document, there is no need to apply BIDI processing. .. These characters are like zero width spaces which have a directional property (but no .. Relationship of destination to this -->
Say you have a repeating address container on an entity record to accommodate multiple address changes. If you format your display template without specifying that each instance of the container needs to be displayed as a unit the result will be a single address in return, no matter how many addresses are entered, and each placeholder will contain the values for all of the addresses - a nonsensical way to display an address list.
When you need to present more than one data element from related records side-by-side. In the previous section we saw how different placeholders referencing the same related records always return separate lists, one per placeholder.
When displayed side-by-side the result is a series of lists rather than the discrete blocks of output for each related item that are more typically desired. George Tilyou Life dates: When you need to set display options for part of a template. You can set the delimiter for repeating values using the delimiter option, or restrict the related items displayed by relationship type or related item type using restrictToRelationshipTypes and restrictToTypes respectively or their counterparts excludeRelationshipTypes and excludeTypes.
When you need to display metadata relating to hierarchical records. When you need to pull metadata through an indirect relationship. In our sample data, this means only the entities related to the primary object can be displayed.
The birthplace data related to each entity cannot. For example, if the primary is an object, and you need to display place data from entities related to objects not places related directly to the objectthe following template would do the job: Thus entities related to objects are grabbed, and then places related to those entities.
Use type identifiers and list multiple types separated by commas. As of version 1. Use relationship type codes and list multiple codes separated by commas. None — no restriction sort One or more bundle specifiers to sort record set on. Specifiers should be relevant to the kind of records retrieved by the relativeTo value. None Direction of sort. None skipWhen An expression to evaluate for each iteration of the unit. This option is useful for filtering specific values in a unit processing repeating values Eg.
Available from version 1. If not set all values are returned. The difference between this and unique is subtle. Take, for example, a unit that formats lists of authors from several related objects. The unique option will eliminate only those lists of authors that are string-wise identical If the authors are in different orders for different objects they will be considered unique values. The aggregateUnique option considers the values used to create those lists, rather than the resulting strings.
If the array of returned values for a unit, prior to conversion to a string, is the same, it is considered a duplicate no matter the order of the authors in the resulting string. Put simply, aggregateUnique applies a more aggressive de-duplication process. If this option is set to 0 or "no" in a unit that references related object representations then all representations will be returned.
This option is available from version 1. For example, to show the first 5 related entities and then a message with the total number: To help make such templates more manageable two tags are available that control output based solely upon their position in a template, obviating the need for long lists of placeholder names.
A metal pan The source for this was: Both tags take a "code" attribute containing one or more bundle specifiers. It is useful when you wish to only show content when the number of values a bundle has is within a range.
For example, if you wish to show a list of related entities only when there are between 2 and 5 relationships: To only show content when the count is a specific number set both min and max to the same number: For example, to output the display only if "current" is selected from the type drop-down in a repeating credit line container: The interlinear annotation characters are used to delimit interlinear annotations in certain circumstances.
They are intended to provide text anchors and delimiters for interlinear annotation for in-process use and are not intended for interchange. The interlinear annotation characters were included in Unicode only in order to reserve code points for very frequent application-internal use.
The interlinear annotation characters are used to delimit interlinear annotations in contexts where other delimiters are not available, and where non-textual means exist to carry formatting information. Many text-processing applications store the text and the associated markup or in some cases styling information of a document in separate structures. The actual text is kept in a single linear structure; additional information is kept separately with pointers to the appropriate text positions.
This is called out-of-band information. The overall implementation makes sure that these two structures are kept in sync.
If the text contains interlinear annotations, it is extremely helpful for implementations to have delimiters in the text itself; even though delimiters are not otherwise used for style markup. With this method, and unlike the case of the object replacement character, all textual information can remain in the standard text stream, but any additional formatting information is kept separately.
In addition, the Interlinear Annotation Anchor serves as a placeholder for formatting information for the whole annotation object, the same way a paragraph mark can be a placeholder to attach paragraph formatting information.
Including interlinear annotation characters in marked-up text does not work because the additional formatting information how to position the annotation, The interlinear annotation characters are also problematic when used in plain text, and are not intended for that purpose. In particular, on older display systems that simply ignore or replace the Interlinear Annotation Characters, the meaning of the text may be changed. The markup to be used in place of the Interlinear Annotation Characters depends on the formatting and nature of the interlinear annotation in question.
Zero-width space - Wikipedia
For ruby, please see [ Ruby ]. When received by a browser as part of marked-up text, they may be ignored. The object replacement character is used to stand in place of an object e. The object replacement character was included in Unicode only in order to reserve a codepoint for a very frequent application-internal use. If the text contains objects such as images, it is extremely helpful for implementations to have a sentinel in the text itself; any additional information is kept separately.
Unicode in XML and other Markup Languages
Including an object replacement character in markup text does not work because the additional information what object to include, The object replacement character is also problematic when used in plain text, because there is no way in plain text to provide the actual object information or a reference to it.
The markup to be used in place of the Object Replacement Character depends on the object in question and the markup context it is used in. These constructs allow providing all additional information needed to identify and use the object in question. Browsers may ignore this character.
When received in an editing context, if the actual object is accessible, editors may either replace the character by the appropriate markup for that object, or otherwise remove it, ideally providing a warning. A series of characters for controlling scope in musical notation.
These characters designate the start and end of common musical constructs. Full musical layout depends on additional information, for example pitch, that cannot be encoded using Unicode. However, many musical symbols may be depicted in isolation and without assigning pitch as part of a textual discussion of music.
Plain text use of Unicode characters is primarily intended for this latter purpose. The scoping operators can be used to support limited renderings of beams, slurs, phrases, etc.
However, in the context of markup languages, musical scoring calls for a dedicated markup language analogous to MathML which would be expected to contain markup for these constructs. These characters duplicate information that can in principle be expressed in markup. Their special code range allows them to be easily filtered, but applications that do not expect them will treat them as garbage characters. Replace with equivalent markup if available.
Browsers may ignore these characters. When received in an editing context, editors may remove or replace them by equivalent markup. A series of characters for expressing language tags, based on existing standards for language tags using the rules in Chapter 16 of [ Unicode ].
These characters allow in-band language tagging in situations where full markup is not available, while allowing easy filtering by applications that do not support them. They were solely included for the benefit of those Internet protocols, such as ACAP, which require a standard mechanism for marking language in UTF-8 strings, and at the same time to avoid the use of other tagging schemes that relied on specific details of the encoding form used. These characters duplicate information that can be expressed in markup.
Replace with equivalent language markup. HTML has the lang attribute. These attributes follow different scoping rules than the tag characters, therefore this replacement will generally not be a simple 1: