B.1.23 VO

Virtual Observatory-specific functions. Some of these are for rather technical purposes.

The UCD parsing functions are based on Grégory Mantelet's library Ucidy corresponding to UCD1+ 1.5, and the VOUnit parsing functions are based on Norman Gray's library Unity corresponding to VOUnits 1.0.

TFCat refers to the Time-Frequency Radio Catalogues format, TFCat 1.0.

ucdStatus( ucd )

Returns a token string giving the category of UCD compliance. UCD1+, UCD1 and SIAv1 ("VOX:")-style UCDs are recognised.

Possible return values are currently:

• "OK": conforms to UCD1+ standard
• "UCD1": looks like a UCD1
• "VOX": is in VOX: namespace introduced by SIAv1
• "BAD_SYNTAX": not a UCD1 and cannot be parsed according to UCD1+
• "BAD_SEQUENCE": UCD words violate UCD1+ sequence rules
• "UNKNOWN_WORD": follows UCD1+ syntax rules but contains non-UCD1+ atom
• "NAMESPACE": follows UCD1+ syntax but contains atoms in non-standard namespace
• "DEPRECATED": contains deprecated UCD1+ words

In the case of non-compliant values, more information can be found using the ucdMessage function.

• Parameters:
  • ucd (String): UCD string
• Return value
  • (String): "OK" for conformant UCD1+, otherwise some other value

ucdMessage( ucd )

Returns a human-readable message associated with the parsing of a UCD. This is expected to be empty for a fully compliant UCD, and may contain error messages or advice otherwise.

• Parameters:
  • ucd (String): UCD value
• Return value
  • (String): message text

vounitStatus( unit )

Returns a token string giving the category of VOUnits compliance.

Possible return values are currently:

• "OK": conforms to VOUnits syntax
• "UNKNOWN_UNIT": parsed as VOUnit but contains unknown base unit(s)
• "GUESSED_UNIT": parsed as VOUnit but contains unknown, though guessable, base unit(s)
• "BAD_SYNTAX": cannot be parsed as VOUnit syntax
• "PARSE_ERROR": unexpected error during parsing
• "USAGE": violates VOUnit usage constraints
• "WHITESPACE": legal VOUnit except that it contains whitespace, which is not allowed by VOUnits

In the case of non-compliant values, more information can be found using the vounitMessage function.

• Parameters:
  • unit (String): unit string
• Return value
  • (String): "OK" for conformant VOUnits, otherwise some other value

vounitMessage( unit )

Returns a human-readable message associated with the parsing of a unit string. This is expected to be empty for a string fully compliant with VOUnits, and may contain error messages or additional information otherwise.

• Parameters:
  • unit (String): unit string
• Return value
  • (String): message text

tfcatStatus( tfcat )

Returns a token string giving the category of TFCat compliance.

Possible return values are currently:

• "OK": conforms to TFCat syntax
• "ERROR": parsed as TFCat, but with one or more errors
• "FAIL": could not be parsed as a TFCat object

For non-OK values, more information can be found using the tfcatMessage function.

• Parameters:
  • tfcat (String): JSON string giving TFCat text
• Return value
  • (String): "OK" for conformant TFCat, otherwise some other value

tfcatMessage( tfcat )

Returns a human-readable message associated with the parsing of a TFCat text. This will be empty for a string fully compliant with the TFCat standard, but will contain error messages otherwise.

• Parameters:
  • tfcat (String): JSON string giving TFCat text
• Return value
  • (String): message text