Commit 0af35eea1a5c1c008e1cab248d1dc5f83ed1e505 - Decoy

Add some notes on modules in Decoy. Chris Pressey 1 year, 4 months ago

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	0	Notes on Decoy Modules
	1	======================
	2
	3	Unclear how much of this belongs to the Decoy language, vs.
	4	how much it belongs to the `decoy` implementation.
	5
	6	We'll start with some simple facts, to try to make the
	7	situation clearer.
	8
	9	### Evaluating Modules
	10
	11	`decoy` is an implementation of Decoy. `decoy` can evaluate modules.
	12
	13	Evaluating a module means two things: creating a new environment
	14	based on the definitions in the module, and evaluating any
	15	bare expressions and displaying the results of them.
	16
	17	When you evaluate a module, it needs to have an implementation
	18	written in Decoy. (But see below.)
	19
	20	When you evaluate a module, it may import other modules.
	21	Or you may supply, on the command line, modules to be
	22	(implicitly) imported beforehand.
	23
	24	Importing a module means evaluating it and providing any
	25	new environment it provides to the module that imported it.
	26
	27	Either way, when you import a module, it too needs to have
	28	an implementation. Usually this implementation is in Decoy.
	29	However in the case of "built-in" modules like (presently)
	30	`stdenv`, the module implementation will be in Lua.
	31
	32	NOTE: This could be the case for other modules too, so that
	33	they could access Lua-specific functionality. But that
	34	goes against the spirit of Decoy, where functions are pure
	35	functions that shouldn't really need access to functionality
	36	specific to a specific platform or language.
	37
	38	### Compiling Modules
	39
	40	As an implementation of Decoy, `decoy` can also compile modules.
	41
	42	Compiling a module means translating it to a module in another
	43	programming language. For the moment we will consider primarily
	44	JavaScript. But Lua and Scheme would other languages we should
	45	consider, since they have very similar operating models.
	46
	47	More TBW