Attributes of block variables

Block variable attributes provide more information about block variables.

The following is a list of block variable attributes.


Block variable attribute	Description
`._cols`	Returns a list of column names.
`._column.[COLUMN]`	Returns a package of metadata for the specified column.
`._data`	The entire result of the query as a table value.
`._defined`	Is the variable or component defined? `@foo._defined`.
`._is_empty`	True if @variable is empty or undefined.
`._length`	Returns the length of a list. `@varlength = @foo._length` In the example above, the block variable `@foo._length` returns the length of the list `@foo`.
`._members`	When applied to a package, yields a list of the package's member names.
`._or_empty`	Returns "" if the variable is undefined, otherwise returns the variable value.
`._pretty`	A string representing a human-readable form of @`variable` (where possible).
`._rows`	Returns the number of rows.
`._tag`	Returns the name of an XML tag. @myvar = <foo bar="5"><baz/></foo> In the example above, the block variable `@myvar._tag` returns the string `foo`.
`._tohtml`	HTML-escaped version of the string form of @`variable`.
`._tojson`	JSON-encoded version of @`variable` (where possible).
`._tostring`	The string form of @`variable`.
`._type`	The variable type. Currently can be list, pkg, xml, value or undefined. `@foo._type`
`._ugly`	A string representing a 1010data input form of @`variable` (where possible).
`._xml`	Returns the code corresponding to the MDB ops as an XML value.