We are going to now indicate the fresh new syntax with the familiar EBNF notation

As yet, so you’re able to establish the newest sentence structure out-of RIF-FLD we relied on “statistical English,” yet another particular English having communicating statistical definitions, advice, etcetera. The next products regarding EBNF notation is stored in mind:

LOCATOR

• New sentence structure of RIF-FLD https://datingranking.net/tr/thaicupid-inceleme/ hinges on the latest signature method and that is not context-100 % free, so EBNF does not bring that it syntax truthfully. Consequently, the newest EBNF grammar describes a rigorous superset from RIF-FLD (not all formulas that will be derivable making use of the EBNF grammar was 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 Term Term . Label, 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 talks of a concrete sentence structure only for investing laws and regulations, and this sentence structure is XML-created, received since a sophistication and you can serialization of EBNF syntax thru brand new presentation-syntax-to-XML mapping for RIF-FLD.

Remaining the aforementioned in your mind, the fresh EBNF sentence structure is visible while the simply a mediator between the fresh mathematical English together with XML. Yet not, moreover it brings a concise view of brand new syntax out-of RIF-FLD and as such they can be handy to have dialect music artists and you may users similar.

For each RIF-FLD algorithm and you may title will likely be prefixed having that recommended 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].