The nodes of a tree from a flat list: the rows of a CSV file, or nodes with
the parent option
A CSV file gives a tree in one of two forms:
| Form | Columns |
|---|---|
| Parent | id, parent, and the other columns. An empty parent makes the root. |
| Path | path, and the other columns. The separator divides a path into its levels. |
The other columns have the names of the options of a node: label,
detail, image, icon, value, color, layout and class. The
fields option of the tree names more columns, and each one becomes a
field of the box with its heading as its name.
In the path form, a level without a row of its own becomes a node with no
options, so home/photos makes the node home too. The identity of a node
is its path without a separator at the start or at the end, such as
home/photos. When the paths start with more than one level, such as
home and var, a root with the label of the separator holds them.
assemble/1 makes the tree from the parent of each node, for both forms of
a file and for the parent option of the DSL.
Summary
Functions
Return the roots of a tree from its entries, in the order of the entries
Return the roots of a tree from the rows of a CSV file
Types
@type entry() :: {Expresso.Element.Node.t(), String.t() | nil, String.t()}
A node, the name of its parent or nil, and the place that gives it, for an error
Functions
@spec assemble([entry()]) :: {:ok, [Expresso.Element.Node.t()]} | {:error, String.t()}
Return the roots of a tree from its entries, in the order of the entries
Each node holds the nodes whose parent it is, after the nodes that it already holds. The function returns an error for two nodes with one name, for a parent that no node has, and for a loop of parents.
iex> alias Expresso.Element.Node
iex> entries = [{%Node{name: "a"}, nil, "a"}, {%Node{name: "b"}, "a", "b"}, {%Node{name: "c"}, "b", "c"}]
iex> {:ok, [root]} = Expresso.Element.Hierarchy.Data.assemble(entries)
iex> {root.name, hd(root.elements).name, hd(hd(root.elements).elements).name}
{"a", "b", "c"}@spec rows([{pos_integer(), [String.t()]}], String.t(), keyword()) :: {:ok, [Expresso.Element.Node.t()]} | {:error, String.t()}
Return the roots of a tree from the rows of a CSV file
rows are the rows of Expresso.Element.Chart.Csv.rows/3, with the
headings first. fields names the columns of the fields, and separator
divides a path.
iex> rows = [{1, ["path", "value"]}, {2, ["/home/photos", "412"]}, {3, ["/var", "21"]}]
iex> {:ok, [root]} = Expresso.Element.Hierarchy.Data.rows(rows, "a.csv", fields: [], separator: "/")
iex> {root.label, Enum.map(root.elements, & &1.name)}
{"/", ["home", "var"]}