id: asdf://asdf-format.org/core/manifests/core-1.6.0
extension_uri: asdf://asdf-format.org/core/extensions/core-1.6.0
title: Core extension 1.6.0
description: Tags for ASDF core objects.
asdf_standard_requirement: 1.6.0
tags:
- tag_uri: tag:stsci.edu:asdf/core/asdf-1.1.0
  schema_uri: http://stsci.edu/schemas/asdf/core/asdf-1.1.0
  title: Top-level schema for every ASDF file.
  description: This schema contains the top-level attributes for every ASDF file.
- tag_uri: tag:stsci.edu:asdf/core/complex-1.0.0
  schema_uri: http://stsci.edu/schemas/asdf/core/complex-1.0.0
  title: Complex number value.
  description: |-
    Represents a complex number matching the following EBNF grammar

    ```
      dot           = "."
      plus-or-minus = "+" | "-"
      digit         = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
      sign          = "" | plus-or-minus
      suffix        = "J" | "j" | "I" | "i"
      inf           = "inf" | "INF"
      nan           = "nan" | "NAN"
      number        = digits | dot digits | digits dot digits
      sci-suffix    = "e" | "E"
      scientific    = number sci-suffix sign digits
      real          = sign number | sign scientific
      imag          = number suffix | scientific suffix
      complex       = real | sign imag | real plus-or-minus imag
    ```

    Though `J`, `j`, `I` and `i` must be supported on reading, it is
    recommended to use `i` on writing.

    For historical reasons, it is necessary to accept as valid complex numbers
    that are surrounded by parenthesis.
- tag_uri: tag:stsci.edu:asdf/core/constant-1.0.0
  schema_uri: http://stsci.edu/schemas/asdf/core/constant-1.0.0
  title: Specify that a value is a constant.
  description: Used as a utility to indicate that value is a literal constant.
- tag_uri: tag:stsci.edu:asdf/core/extension_metadata-1.0.0
  schema_uri: http://stsci.edu/schemas/asdf/core/extension_metadata-1.0.0
  title: Metadata about specific ASDF extensions that were used to create this file.
  description: Metadata about specific ASDF extensions that were used to create this
    file.
- tag_uri: tag:stsci.edu:asdf/core/externalarray-1.0.0
  schema_uri: http://stsci.edu/schemas/asdf/core/externalarray-1.0.0
  title: Point to an array-like object in an external file.
  description: |-
    Allow referencing of array-like objects in external files. These files can be
    any type of file and in any absolute or relative location to the asdf file.
    Loading of these files into arrays is not handled by asdf.
- tag_uri: tag:stsci.edu:asdf/core/history_entry-1.0.0
  schema_uri: http://stsci.edu/schemas/asdf/core/history_entry-1.0.0
  title: An entry in the file history.
  description: |-
    A record of an operation that has been performed
    upon a file.
- tag_uri: tag:stsci.edu:asdf/core/integer-1.1.0
  schema_uri: http://stsci.edu/schemas/asdf/core/integer-1.1.0
  title: Arbitrary precision integer value.
  description: Represents an arbitrarily large integer value.
- tag_uri: tag:stsci.edu:asdf/core/ndarray-1.1.0
  schema_uri: http://stsci.edu/schemas/asdf/core/ndarray-1.1.0
  title: An *n*-dimensional array.
  description: |-
    There are two ways to store the data in an ndarray.

    - Inline in the tree: This is recommended only for small arrays.  In
      this case, the entire ``ndarray`` tag may be a nested list, in
      which case the type of the array is inferred from the content.
      (See the rules for type inference in the ``inline-data``
      definition below.)  The inline data may also be given in the
      ``data`` property, in which case it is possible to explicitly
      specify the ``datatype`` and other properties.

    - External to the tree: The data comes from a [block](ref:block)
      within the same ASDF file or an external ASDF file referenced by a
      URI.
- tag_uri: tag:stsci.edu:asdf/core/software-1.0.0
  schema_uri: http://stsci.edu/schemas/asdf/core/software-1.0.0
  title: Describes a software package.
  description: General-purpose description of a software package.
