View Source Table.Reader protocol (Table v0.1.0)
A protocol to read tabular data.
Link to this section Summary
Functions
Returns information on how to traverse the given tabular data.
Link to this section Types
@type column_reader() :: {:columns, metadata(), Enumerable.t()}
Describes column-based traversal.
The enumerable should yield columns, where each column is a series of values. The columns should have the same order as columns in the metadata.
@type metadata() :: %{columns: [Table.column()]}
Table metadata.
@type row_reader() :: {:rows, metadata(), Enumerable.t()}
Describes row-based traversal.
The enumerable should yield rows, where each row is a series of values. The values should follow the order of columns in the metadata.
@type t() :: term()
Link to this section Functions
@spec init(t()) :: row_reader() | column_reader() | :none
Returns information on how to traverse the given tabular data.
There are generally two distinct ways of traversing tabular data, that is, a row-based one and a column-based one. Depending on the underlying data representation, one of them is more natural and more efficient.
The init/1 return value describes either of the two traversal
types, see row_reader/0 and column_reader/0 respectively.
Some structs may be tabular only in a subset of cases, therefore
:none may be returned to indicate that there is no valid data to
read.