Feature:ScalarExpressionsInTriplePatterns

From SPARQL Working Group
Jump to: navigation, search


Feature: Scalar Expressions In Triple Patterns

In a triple patterns, an expression can be written instead of a variable. TCompiler reThat is replaced to an unique blank node and syntax sugarShort summary (one or two sentences max), explaining the capability that this feature provides.

Feature description

The syntax

{ ?bad-part <serial> ?s-no .
  optional { ?suspicious-before <serial> `?s-no - 1` }
  optional { ?suspicious-after <serial> `?s-no + 1` }
}

is more convenient than

{ ?bad-part <serial> ?s-no .
  optional { ?suspicious-before <serial> ?s-no-minus-1 . filter { ?s-no-minus-1 = ?s-no - 1) }
  optional { ?suspicious-before <serial> ?s-no-plus-1 . filter { ?s-no-plus-1 = ?s-no + 1) }
}

so the grammer for triple patterns can be extendeed to allow expression in backquotes as a replacement for combination of blank node variable and a filter.

Example

e.g. sample Query highlighting necessary syntax extensions, expected output, or modified/extended result format, endpoint self description mock-up syntax, etc.

Existing Implementation(s)

  • Virtuoso

Existing Specification / Documentation

List any existing text that attempts a formal definition of this extension. This could be a draft specification, API or syntax documentation, etc.

Compatibility

The backquote character was not in use in the SPARQL grammer before so the compatibility is guaranteed.

Links to postponed Issues

Has this extension/use case some history in the group already? I.e. are there posponed issues or archived mail-threads related to this originating from DAWG?

Related Features

List and possibly link to other use cases or extensions that relate to that use case. That will help us grouping them together in the end.

Champions

OpenLink

Use cases

A description of one or more use cases, the solution of which requires this feature. Multiple use cases can be added to each feature.

References