---
name: "Attean::API::Expression"
section: "3pm"
platform: "linux"
package: "libattean-perl"
version: "0.035-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Attean::API::Expression"
---

# Attean::API::Expression(3pm)

SPARQL expressions

## NAME

Attean::API::Expression - SPARQL expressions

## VERSION

This document describes Attean::API::Expression version 0.035

## DESCRIPTION

The Attean::API::Expression role defines a common API for SPARQL expressions consisting of logical, numeric, and function operators, constant terms, and variables. Expressions may be evaluated in the context of a Attean::API::Result object, and either return a Attean::API::Term object or throw a type error exception.

## ROLES

This role consumes the Attean::API::DirectedAcyclicGraph role which provide the following methods:

- "is\_leaf"

  - "walk( prefix =\> \\&pre\_cb, postfix =\> \\&pre\_cb )"

  - "cover( prefix =\> \\&pre\_cb, postfix =\> \\&pre\_cb )"

  and the following attributes:

- "children"

  ## ATTRIBUTES

The following attributes exist:

- "operator"

  A string indicating the expression operator (e.g. `'+'` or `'||'`).

## REQUIRED METHODS

The following methods are required by the Attean::API::Expression role:

- "as\_string"

  Returns a string serialization of the expression object.

## BUGS

Please report any bugs or feature requests to through the GitHub web interface at \<https://github.com/kasei/attean/issues\>.

## SEE ALSO

## AUTHOR

Gregory Todd Williams  `"<gwilliams@cpan.org>"`

## COPYRIGHT

Copyright (c) 2014--2022 Gregory Todd Williams. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.