File structure

The three top-level keys of a workbook.

title: <text>            # optional
params:                  # optional
  <name>: <parameter>
nodes:
  <name>:
    <step>: <specification>
    <step>: <specification>

Key	Type	Meaning
`title`	text	The workbook’s name. The Lab shows the problem’s own title; this one documents the file. (`question`, its former name, is still read.)
`params`	mapping	Parameters, by name.
`nodes`	mapping	The nodes, by name, each an ordered mapping of steps.

Any other top-level key is an error.

Names

Node and parameter names consist of letters, digits and _, and start with a letter or _. A name cannot be both a node and a parameter, and two nodes cannot share a name.

Node rules

A node has at least one step.
Its first step reads data: series, regions, from, join, python or typescript. A node may also consist of a single chart, map, correlate or holdout step with its own from.
python and typescript steps are nodes of their own.
chart and map are the last step of a node.
on and how, written at the node’s level, belong to its join step.