We will now indicate the fresh new sentence structure with the common EBNF notation

Until now, so you’re able to identify the fresh new sentence structure of RIF-FLD we relied on «analytical English,» a unique types of English having connecting mathematical meanings, examples, an such like. The second facts about the EBNF notation will likely be kept in mind:

LOCATOR

• This new syntax of RIF-FLD hinges on the fresh new signature method which is perhaps not perspective-totally free, very EBNF does not need it syntax precisely. As a result, this new EBNF grammar defines a rigorous superset regarding RIF-FLD (not totally all algorithms which might be https://datingranking.net/tr/zoosk-inceleme/ derivable using the EBNF grammar try well-formed).
• The EBNF syntax is not a concrete syntax: it does not address the details of how constants (defined in [RIF-DTB]) and variables are represented, and it is not sufficiently precise about the delimiters and escape symbols. White space is informally used as a delimiter, and is implied in productions that use Kleene star. For instance, TERM* is to be understood as Label Label . Name, where each ‘ ‘ abstracts from one or more blanks, tabs, newlines, etc. This is done intentionally since RIF’s presentation syntax is used as a tool for specifying the semantics and for illustration of the main RIF concepts through examples.
• RIF defines a tangible sentence structure just for selling and buying laws and regulations, hence syntax is XML-created, received as a refinement and you can serialization of one’s EBNF sentence structure thru brand new demonstration-syntax-to-XML mapping for RIF-FLD.

Remaining the above in your mind, the newest EBNF sentence structure is seen since merely an intermediary ranging from the latest statistical English as well as the XML. Yet not, what’s more, it gets a brief view of brand new sentence structure from RIF-FLD and as such they can be handy to possess dialect painters and you can users similar.

Each RIF-FLD formula and you can label should be prefixed that have one

Place for ADS

optional annotation

The RIF-FLD presentation syntax does not commit to any particular vocabulary and permits arbitrary sequences of Unicode characters in constant symbols, argument names, and variables. Such sequences are denoted with UNICODESTRING in the above syntax. Constant symbols have this form: "UNICODESTRING"^^SYMSPACE, where SYMSPACE is a ANGLEBRACKIRI or CURIE that represents the identifier of the symbol space of the constant. UNICODESTRING, ANGLEBRACKIRI, and CURIE are defined in Section Shortcuts for Constants in RIF’s Presentation Syntax of [RIF-DTB]. Constant symbols can also have several shortcut forms, which are represented by the non-terminal CONSTSHORT. These shortcuts are also defined in the same section of [RIF-DTB]. One of them is the CURIE shortcut, which is used in the examples in this document. Names are Unicode character sequences that form valid XML NCNames [XML-Names]. Variables are composed of Names prefixed with a ?-sign.

, which is used in several places in the grammar, is a non-terminal whose definition is left to the dialects. It is intended to specify the protocol by which external sources, remote modules, and imported RIF documents are located. This must include the basic form , where IRI is a Unicode string in the form of an absolute IRI.

The symbols NEWCONNECTIVE, NEWQUANTIFIER, NEWAGGRFUNC, and NEWTERM are RIF-FLD extension points. They are not actual symbols in the alphabet. Instead, dialects are supposed to replace NEWCONNECTIVE, NEWQUANTIFIER, and NEWAGGRFUNC, by zero or more actual new symbols, while NEWTERM is to be replaced by zero or more new kinds of terms. Note that the extension point NEWSYMBOL is not shown in the EBNF grammar completely avoids mentioning the alphabet of the language (which is infinite).

IRIMETA, for identification and metadata. IRIMETA is represented using (*. *)-brackets that contain an optional rif:iri constant as identifier followed by an optional Figure or cones as metadata. One such specialization is '"' IRI '"^^' 'rif:iri' from the Const production, where IRI is a sequence of Unicode characters that forms an internationalized resource identifier as defined by [RFC-3987].