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Data Types

Identifiers​

The identifiers refer to base characteristics of the objects. They are defined as unquoted ASCII alphanumeric sequences; the underscore (_) is also allowed except in the initial position.

note

Reserved words such as and, true, etc. cannot be used as identifiers.

Examples:

  • size
  • object_id
  • recursion_level
  • ctime

See Common Object Data for more examples.

Metadata Keys​

Metadata keys refer to specific keys in an object's or its relation metadata, which have a form of key-value entries. The metadata key names are prefixed with $ and are only meant to be used within metadata related functions (such as has_object_meta or match_object_meta).

Examples:

  • $natural_language
  • $iso9660.bootable

Strings​

The literal strings are defined as a double quote (") wrapped sequence of Unicode characters. Additionally the following escape sequences are defined (escaped -> unescaped):

  • \" -> " (mandatory escape)
  • \\ -> \ (mandatory escape)
  • \/ -> /
  • \b -> backspace U+0008
  • \f -> form feed U+000c
  • \n -> newline U+000a
  • \r -> carriage return U+000d
  • \t -> horizontal tab U+0009
  • \uNNNN -> single Unicode character NNNN
note

Whitespace is significant inside strings.

Examples:

  • "a string"
  • "another \"string\""

Integer numbers (Integer)​

Numeric values are represented as sequences of ASCII digit characters, optionally preceded by a + or - sign.

Examples:

  • 1337
  • +10
  • -42

Floating point numbers (Number)​

These floating point numbers are defined as:

  • integer numbers
  • integer numbers followed by a . subsequently followed by a fractional part

The fractional part is expressed as a sequence of ASCII digits optionally followed by an exponent part. The exponent part is expressed as the e letter followed by an integer number.

Examples:

  • 1
  • -123.456
  • 123.456e-7

Date and Time (DateTime)​

The time functions accept dates (with optional times) as strings in the following format:

  • "YYYY-MM-DD"
  • "YYYY-MM-DD hh:mm:ss"

Examples:

  • "2024-09-26"
  • "2024-09-26 13:37:00"

Boolean values​

The boolean values are either true or false.

note

The above values are both reserved words.