id3

type Case struct {
	Value  string    // The distinct column value.
	Class  string    // The decided class value, or "" if further decision(s) are needed.
	Decide *Decision // The subsequent decision, or nil.
}

type Decision struct {
	Column string  // The name of the data column.
	Cases  []*Case // The cases for that column.
}

type Distinct struct {
	Value       string
	Probability float64
}

type View interface {

	// Columns returns the column names in this view. Columns with names of ""
	// have been hidden from this view - see Drop method.
	//
	Columns() []string

	// First returns to before the first row in this view.
	//
	First()

	// Next returns the next row in the view, or nil if there are no more
	// rows.
	//
	Next() []string

	// Select returns a view that shows only rows having the given value in the
	// column.
	//
	Select(column, value string) View

	// Drop returns a view which 'hides' the named column.
	//
	Drop(column string) View
}