Commit a5fc8ad269ffe44f6ba8b8bbad5c1385284cbf0d - UampirNexol

Describe situation of the evaluator code better. Chris Pressey 13 days ago

1 changed file(s) with 13 addition(s) and 4 deletion(s). Raw diff Collapse all Expand all

+13

-4

src/Language/UampirNexol/Eval.hs less more

4	4	module Language.UampirNexol.Eval where
5	5
6	6	--
7		-- Evaluator for UampirNexol expressions. The evaluator is not meant to have
8		-- value as something that is run, so much as something that describes
9		-- meanings of (and can thus assign meanings to) UampirNexol expressions.
	7	-- Evaluator for UampirNexol expressions.
	8	--
	9	-- The evaluator is not meant to have value as something that is executed,
	10	-- so much as something that describes meanings of (and can thus assign
	11	-- meanings to) UampirNexol expressions.
	12	--
	13	-- The definition of the evaluator given here is also very poor. Better
	14	-- would be if the set of Values included functions. A typical UampirNexol
	15	-- program is a function taking states to states. Evaluating such an
	16	-- expression should result in a function value. But the way we have it
	17	-- here, necessarily we need to apply that function to a (state) value.
	18	-- We should change that.
10	19	--
11	20
12	21	import qualified Data.Map as Map

30	39	let
31	40	i = case eval expr env v of
32	41	(Const (IntLit this)) -> this
33		other -> error $ "eek: " ++ (show other)
	42	other -> error $ "eek: " ++ (show other)
34	43	i' = i `mod` 256
35	44	z' = if i' == 0 then 1 else 0
36	45	n' = if i' > 127 then 1 else 0