learn

type Lesson struct {
	ID, Title, Summary string
	Steps              []Step
}

type Step struct {
	// Text is the prose shown to the learner. It carries no line breaks, so the
	// UI may wrap it at any width.
	Text string
	// Setup is played onto a fresh game before the step, in game notation.
	Setup []string
	// Highlight marks holes the UI should call out.
	Highlight []game.Point
	// Task, when non-nil, requires the learner to make a move before
	// continuing.
	Task *Task
}

type Task struct {
	Prompt string
	// Answer is one hole that satisfies the task, so the UI can show the
	// learner an answer once they have struggled. Where several moves are
	// right, it is the one the prose talks about.
	Answer game.Point
	// Accept reports whether the learner's move satisfies the step, and returns
	// the feedback to show either way.
	//
	// It is given the position the step set up, with the learner's side to
	// move, and the hole the learner chose, including holes the learner is not
	// allowed to use: the two mistakes beginners actually make, reaching into
	// the opponent's border line and reaching for a corner, are illegal moves,
	// and a learner who is silently stopped from making them is never told why.
	// So the UI must pass the raw choice through rather than filtering it, and
	// play it onto the board only when Accept returns true. Accept never
	// modifies the game it is given.
	Accept func(g *game.Game, played game.Point) (ok bool, feedback string)
}