Commit b03cf379abf6d12ab97fa3de16c324a8a464ba5b - s-cargot

Added docs for WellFormed cons/uncons Getty Ritter 10 years ago

1 changed file(s) with 11 addition(s) and 0 deletion(s). Collapse all Expand all

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Data/SCargot/Repr/WellFormed.hs less more

30	30	import Control.Applicative ((<$>), (<*>), pure)
31	31	import Data.SCargot.Repr as R
32	32
	33	-- \| Produce the head and tail of the s-expression (if possible).
	34	--
	35	-- >>> uncons (L [A "el", A "eph", A "ant"])
	36	-- Just (WFSAtom "el",WFSList [WFSAtom "eph",WFSAtom "ant"])
33	37	uncons :: WellFormedSExpr a -> Maybe (WellFormedSExpr a, WellFormedSExpr a)
34	38	uncons R.WFSAtom {} = Nothing
35	39	uncons (R.WFSList (x:xs)) = Just (x, R.WFSList xs)
36	40
	41	-- \| Combine the two-expressions into a new one. This will return
	42	-- @Nothing@ if the resulting s-expression is not well-formed.
	43	--
	44	-- >>> cons (A "el") (L [A "eph", A "ant"])
	45	-- Just (WFSList [WFSAtom "el",WFSAtom "eph",WFSAtom "ant"])
	46	-- >>> cons (A "pachy") (A "derm"))
	47	-- Nothing
37	48	cons :: WellFormedSExpr a -> WellFormedSExpr a -> Maybe (WellFormedSExpr a)
38	49	cons _ (R.WFSAtom {}) = Nothing
39	50	cons x (R.WFSList xs) = Just (R.WFSList (x:xs))