ehmry/dhall-haskell
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Add List/last

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This commit is contained in:
Gabriel Gonzalez 2016-09-16 09:04:08 -07:00
parent a0a2c54671
commit 1741db3702
3 changed files with 21 additions and 0 deletions
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14
src/Dhall/Core.hs
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@ -203,6 +203,8 @@ data Expr a
| ListFold
-- | > ListFirst ~ List/first
| ListFirst
-- | > ListLast ~ List/last
| ListLast
-- | > ListIndexed ~ List/indexed
| ListIndexed
-- | > ListConcat x y ~ x ++ y
@ -268,6 +270,7 @@ instance Monad Expr where
ListBuild >>= _ = ListBuild
ListFold >>= _ = ListFold
ListFirst >>= _ = ListFirst
ListLast >>= _ = ListLast
ListIndexed >>= _ = ListIndexed
ListConcat l r >>= k = ListConcat (l >>= k) (r >>= k)
Maybe >>= _ = Maybe
@ -419,6 +422,8 @@ buildExpr5 ListFold =
"List/fold"
buildExpr5 ListFirst =
"List/first"
buildExpr5 ListLast =
"List/last"
buildExpr5 ListIndexed =
"List/indexed"
buildExpr5 List =
@ -1434,6 +1439,8 @@ typeWith _ ListFold = do
(Pi "nil" "list" "list")) ) ) )
typeWith _ ListFirst = do
return (Pi "a" (Const Type) (Pi "_" (App List "a") (App Maybe "a")))
typeWith _ ListLast = do
return (Pi "a" (Const Type) (Pi "_" (App List "a") (App Maybe "a")))
typeWith _ ListIndexed = do
let kts = [("_1", Natural), ("_2", "a")]
return
@ -1557,6 +1564,13 @@ normalize e = case e of
cons' y ys = App (App cons y) ys
App (App ListFirst _) (ListLit t ys) ->
normalize (MaybeLit t (Data.Vector.take 1 ys))
App (App ListLast _) (ListLit t ys) ->
normalize (MaybeLit t y)
where
y =
if Data.Vector.null ys
then Data.Vector.empty
else Data.Vector.singleton (Data.Vector.last ys)
App (App ListIndexed _) (ListLit t xs) ->
normalize (ListLit t' (fmap adapt (Data.Vector.indexed xs)))
where

4
src/Dhall/Lexer.x
View File

@ -89,6 +89,7 @@ tokens :-
"List/build" { emit ListBuild }
"List/fold" { emit ListFold }
"List/first" { emit ListFirst }
"List/last" { emit ListLast }
"List/indexed" { emit ListIndexed }
"Maybe" { emit Maybe }
"Maybe/fold" { emit MaybeFold }
@ -198,6 +199,7 @@ data Token
| ListBuild
| ListFold
| ListFirst
| ListLast
| ListIndexed
| Maybe
| MaybeFold
@ -292,6 +294,8 @@ instance Buildable Token where
= "List/build"
build ListFirst
= "List/first"
build ListLast
= "List/last"
build ListIndexed
= "List/indexed"
build ListFold

3
src/Dhall/Parser.y
View File

@ -79,6 +79,7 @@ import qualified NeatInterpolation
'List/build' { Dhall.Lexer.ListBuild }
'List/fold' { Dhall.Lexer.ListFold }
'List/first' { Dhall.Lexer.ListFirst }
'List/last' { Dhall.Lexer.ListLast }
'List/indexed' { Dhall.Lexer.ListIndexed }
'Maybe' { Dhall.Lexer.Maybe }
'Maybe/fold' { Dhall.Lexer.MaybeFold }
@ -180,6 +181,8 @@ Expr5
{ ListFold }
| 'List/first'
{ ListFirst }
| 'List/last'
{ ListLast }
| 'List/indexed'
{ ListIndexed }
| 'Maybe'