*** Relations involving values
(Character who learns new actions by watching the player; For Demonstration Purposes)
A character who learns new actions by watching the player performing them.

Suppose we want to have a character who can dynamically learn new actions by observing the player performing them. We could do this by adding the actions to a list of things the character can do, but using a relation to express the same idea allows for tidier, easier-to-read code.

Thanks to Jesse McGrew for the initial design of this example.

	{*}"For Demonstration Purposes"
	
	Section 1 - Procedure
	
	Capability relates various people to various stored actions. The verb to be capable of means the capability relation. 

	Persuasion rule: 
		let CA be the current action with no specific actor; 
		if the person asked is capable of CA:
			persuasion succeeds; 
		otherwise:
			say "[The person asked] look[s] confused. Maybe a demonstration would help.";
			persuasion fails.

	The action requester is an object that varies. The action requester variable translates into I6 as "act_requester". 

	To decide which action is the current action with no specific actor: 
		let old actor be the person asked; 
		let old requester be the action requester; 
		now the person asked is the player; 
		now the action requester is nothing; 
		let CA be the current action; 
		now the person asked is the old actor; 
		now the action requester is the old requester; 
		decide on CA.
	
	The learning by observation rule is listed after the report stage rule in the specific action-processing rules.
	
	Definition: a person is other if he is not the player.
	
	This is the learning by observation rule:
		repeat with the viewer running through other people who can see the player:
			if the player is the actor and viewer is not capable of the current action: 
				say "[The viewer] watches your behavior with interest. Seems like [they] [are] learning.";
				now the viewer is capable of the current action.
		
	Section 2 - Scenario
	
	The Daily Planet is a room. Clark is here. He is a man. 
	
	When play begins: 
		now Clark is capable of taking inventory. 
	
	Test me with "Clark, inventory / Clark, x me / x me / Clark, x me".