elm/compiler/Generate/JavaScript.hs

361 lines
13 KiB
Haskell

module Generate.JavaScript (jsModule) where
import Control.Arrow (first,second)
import Control.Monad (liftM,(<=<),join,ap)
import Data.Char (isAlpha,isDigit)
import qualified Data.List as List
import qualified Data.Map as Map
import qualified Data.Set as Set
import Data.Either (partitionEithers)
import qualified Text.Pandoc as Pan
import Unique
import Generate.Cases
import SourceSyntax.Everything
import SourceSyntax.Location
import qualified Transform.SortDefinitions as SD
indent = concatMap f
where f '\n' = "\n "
f c = [c]
internalImports name =
[ ("N" , "Elm.Native"),
("_N", "N.Utils(elm)"),
("_L", "N.List(elm)"),
("_E", "N.Error(elm)"),
("_J", "N.JavaScript(elm)"),
("_str", "_J.toString"),
("$moduleName", quoted name)
]
parens s = "(" ++ s ++ ")"
brackets s = "{" ++ s ++ "}"
commaSep = List.intercalate ", "
dotSep = List.intercalate "."
jsObj = brackets . commaSep
jsList ss = "["++ List.intercalate "," ss ++"]"
jsFunc args body = "function(" ++ args ++ "){" ++ indent body ++ "}"
assign x e = "\nvar " ++ x ++ " = " ++ e ++ ";"
ret e = "\nreturn "++ e ++";"
quoted s = "'" ++ concatMap f s ++ "'"
where f '\n' = "\\n"
f '\'' = "\\'"
f '\t' = "\\t"
f '\"' = "\\\""
f '\\' = "\\\\"
f c = [c]
globalAssign n e = "\n" ++ assign' n e ++ ";"
assign' n e = n ++ " = " ++ e
jsModule :: MetadataModule t v -> String
jsModule modul =
run $ do
body <- toJS . fst . SD.flattenLets [] $ program modul
foreignImport <- mapM importEvent (foreignImports modul)
return $ concat [ setup ("Elm": names modul)
, globalAssign ("Elm." ++ modName)
(jsFunc "elm" $ makeProgram body foreignImport) ]
where
modName = dotSep (names modul)
makeProgram body foreignImport =
concat [ "\nvar " ++ usefulFuncs ++ ";"
, concatMap jsImport (imports modul)
, concat foreignImport
, assign "_op" "{}"
, body
, concatMap exportEvent $ foreignExports modul
, jsExports
]
setup names = concatMap (\n -> globalAssign n $ n ++ " || {}") .
map dotSep . drop 2 . List.inits $ init names
usefulFuncs = commaSep (map (uncurry assign') (internalImports modName))
jsExports = setup ("elm" : names modul) ++
ret (assign' ("elm." ++ modName) (brackets exs))
where
exs = indent . commaSep . concatMap pair $ "_op" : exports modul
pair x | isOp x = []
| otherwise = ["\n" ++ x ++ " : " ++ x]
importEvent (js,base,elm,_) =
do v <- toJS' base
return $ concat [ "\nvar " ++ elm ++ "=Signal.constant(" ++ v ++ ");"
, "\ndocument.addEventListener('", js
, "_' + elm.id, function(e) { elm.notify(", elm
, ".id, e.value); });" ]
exportEvent (js,elm,_) =
concat [ "\nA2( Signal.lift, function(v) { "
, "var e = document.createEvent('Event');"
, "e.initEvent('", js, "_' + elm.id, true, true);"
, "e.value = v;"
, "document.dispatchEvent(e); return v; }, ", elm, ");" ]
jsImport (modul, method) =
concat $ zipWith3 (\s n v -> s ++ assign' n v ++ ";") starters subnames values
where
starters = "\nvar " : repeat "\n"
values = map (\name -> name ++ " || {}") (init subnames) ++
["Elm." ++ modul ++ parens "elm"]
subnames = map dotSep . tail . List.inits $ split modul
split names = case go [] names of
(name, []) -> [name]
(name, ns) -> name : split ns
go name str = case str of
'.':rest -> (reverse name, rest)
c:rest -> go (c:name) rest
[] -> (reverse name, [])
class ToJS a where
toJS :: a -> Unique String
instance ToJS (Def t v) where
-- TODO: Make this handle patterns besides plain variables
toJS (Def (PVar x) e)
| isOp x = globalAssign ("_op['" ++ x ++ "']") `liftM` toJS' e
| otherwise = assign x `liftM` toJS' e
toJS (Def pattern e@(L s _)) =
do n <- guid
let x = "_" ++ show n
var = L s . Var
toDef y = Def (PVar y) (L s $ Case (var x) [(pattern, var y)])
stmt <- assign x `liftM` toJS' e
vars <- toJS . map toDef . Set.toList $ SD.boundVars pattern
return (stmt ++ vars)
toJS (TypeAnnotation _ _) = return ""
instance ToJS a => ToJS [a] where
toJS xs = concat `liftM` mapM toJS xs
toJS' :: LExpr t v -> Unique String
toJS' (L span expr) =
case expr of
MultiIf ps -> multiIfToJS span ps
Case e cases -> caseToJS span e cases
_ -> toJS expr
remove x e = "_N.remove('" ++ x ++ "', " ++ e ++ ")"
addField x v e = "_N.insert('" ++ x ++ "', " ++ v ++ ", " ++ e ++ ")"
setField fs e = "_N.replace(" ++ jsList (map f fs) ++ ", " ++ e ++ ")"
where f (x,v) = "['" ++ x ++ "'," ++ v ++ "]"
access x e = e ++ "." ++ x
makeRecord kvs = record `liftM` collect kvs
where
combine r (k,v) = Map.insertWith (++) k v r
collect = liftM (List.foldl' combine Map.empty) . mapM prep
prep (k, e) =
do v <- toJS' e
return (k, [v])
fields fs =
brackets ("\n "++List.intercalate ",\n " (map (\(k,v) -> k++":"++v) fs))
hidden = fields . map (second jsList) .
filter (not . null . snd) . Map.toList . Map.map tail
record kvs = fields . (("_", hidden kvs) :) . Map.toList . Map.map head $ kvs
instance ToJS Literal where
toJS lit =
case lit of
Chr c -> return $ quoted [c]
Str s -> return $ "_str" ++ parens (quoted s)
IntNum n -> return $ show n
FloatNum n -> return $ show n
Boolean b -> return $ if b then "true" else "false"
instance ToJS (Expr t v) where
toJS expr =
case expr of
Var x -> return x
Literal lit -> toJS lit
Range lo hi -> jsRange `liftM` toJS' lo `ap` toJS' hi
Access e x -> access x `liftM` toJS' e
Remove e x -> remove x `liftM` toJS' e
Insert e x v -> addField x `liftM` toJS' v `ap` toJS' e
Modify e fs -> do fs' <- (mapM (\(x,v) -> (,) x `liftM` toJS' v) fs)
setField fs' `liftM` toJS' e
Record fs -> makeRecord fs
Binop op e1 e2 -> binop op e1 e2
Lambda p e@(L s _) -> liftM fastFunc (toJS' body)
where
fastFunc body
| length args < 2 || length args > 9 =
foldr (\arg bod -> jsFunc arg (ret bod)) body args
| otherwise =
"F" ++ show (length args) ++ parens (jsFunc (commaSep args) (ret body))
(args, body) = first reverse $ foldr depattern ([], innerBody) (zip patterns [1..])
depattern (pattern,n) (args, body) =
case pattern of
PVar x -> (x : args, body)
_ -> let arg = "arg" ++ show n
in (arg:args, L s (Case (L s (Var arg)) [(pattern, body)]))
(patterns, innerBody) = collect [p] e
collect patterns lexpr@(L _ expr) =
case expr of
Lambda p e -> collect (p:patterns) e
_ -> (patterns, lexpr)
App e1 e2 -> jsApp e1 e2
Let defs e -> jsLet $ SD.flattenLets defs e
ExplicitList es ->
do es' <- mapM toJS' es
return $ "_J.toList" ++ parens (jsList es')
Data name es ->
do fs <- mapM toJS' es
return $ case name of
"[]" -> jsNil
"::" -> jsCons (head fs) ((head . tail) fs)
_ -> jsObj $ ("ctor:" ++ show name) : fields
where fields = zipWith (\n e -> "_" ++ show n ++ ":" ++ e) [0..] fs
Markdown doc -> return $ "Text.text('" ++ pad ++ md ++ pad ++ "')"
where pad = "<div style=\"height:0;width:0;\">&nbsp;</div>"
md = formatMarkdown $ Pan.writeHtmlString Pan.def doc
jsApp e1 e2 =
do f <- toJS' func
as <- mapM toJS' args
return $ case as of
[a] -> f ++ parens a
_ -> "A" ++ show (length as) ++ parens (commaSep (f:as))
where
(func, args) = go [e2] e1
go args e =
case e of
(L _ (App e1 e2)) -> go (e2 : args) e1
_ -> (e, args)
formatMarkdown = concatMap f
where f '\'' = "\\'"
f '\n' = "\\n"
f '"' = "\""
f c = [c]
multiIfToJS span ps =
case last ps of
(L _ (Var "otherwise"), e) -> toJS' e >>= \b -> format b (init ps)
_ -> format ("_E.If" ++ parens ("$moduleName," ++ quoted (show span))) ps
where
format base ps =
foldr (\c e -> parens $ c ++ " : " ++ e) base `liftM` mapM f ps
f (b,e) = do b' <- toJS' b
e' <- toJS' e
return (b' ++ " ? " ++ e')
jsLet (defs,e') = do ds <- mapM toJS defs
e <- toJS' e'
return $ jsFunc "" (concat ds ++ ret e) ++ "()"
caseToJS span e ps = do
(tempVar,match) <- caseToMatch ps
e' <- toJS' e
let (match',stmt) = case e of
L _ (Var x) -> (matchSubst [(tempVar,x)] match, "")
_ -> (match, assign tempVar e')
matches <- matchToJS span match'
return $ jsFunc "" (stmt ++ matches) ++ "()"
matchToJS span match =
case match of
Match name clauses def ->
do cases <- concat `liftM` mapM (clauseToJS span name) clauses
finally <- matchToJS span def
let isLiteral p = case p of
Clause (Right _) _ _ -> True
_ -> False
access = if any isLiteral clauses then "" else ".ctor"
return $ concat [ "\nswitch (", name, access, ") {"
, indent cases, "\n}", finally ]
Fail -> return ("_E.Case" ++ parens ("$moduleName," ++ quoted (show span)))
Break -> return "break;"
Other e -> ret `liftM` toJS' e
Seq ms -> concat `liftM` mapM (matchToJS span) (dropEnd [] ms)
where
dropEnd acc [] = acc
dropEnd acc (m:ms) =
case m of
Other _ -> acc ++ [m]
_ -> dropEnd (acc ++ [m]) ms
clauseToJS span var (Clause value vars e) = do
let vars' = map (\n -> var ++ "._" ++ show n) [0..]
s <- matchToJS span $ matchSubst (zip vars vars') e
pattern <- case value of
Right (Boolean True) -> return "true"
Right (Boolean False) -> return "false"
Right lit -> toJS lit
Left name -> return . quoted $ case List.elemIndices '.' name of
[] -> name
is -> drop (last is + 1) name
return $ concat [ "\ncase ", pattern, ":", indent s ]
jsNil = "_L.Nil"
jsCons e1 e2 = "_L.Cons(" ++ e1 ++ "," ++ e2 ++ ")"
jsRange e1 e2 = "_L.range" ++ parens (e1 ++ "," ++ e2)
jsCompare e1 e2 op = parens ("_N.cmp(" ++ e1 ++ "," ++ e2 ++ ")" ++ op)
binop op e1 e2
| op == "Basics.." =
do ss <- mapM toJS' (e1 : collect [] e2)
return . jsFunc "$" . ret $ apply "$" ss
| op == "Basics.<|" =
do arg <- toJS' e2
funcs <- mapM toJS' (collect [] e1)
return (apply arg funcs)
| otherwise =
binopNormal op `liftM` toJS' e1 `ap` toJS' e2
where
apply = foldr (\f arg-> f ++ parens arg)
collect es e =
case e of
L _ (Binop op e1 e2) | op == "Basics.." -> collect (es ++ [e1]) e2
_ -> es ++ [e]
binopNormal op s1 s2 =
case Map.lookup op opDict of
Just e -> e
Nothing -> "A2" ++ parens (commaSep [ prefix ++ func, s1, s2 ])
where
func | isOp op' = "_op['" ++ op' ++ "']"
| otherwise = op'
(prefix, op') = case List.elemIndices '.' op of
[] -> ("", op)
xs -> splitAt (last xs + 1) op
opDict = Map.fromList $ basics ++
[ ("::", jsCons s1 s2)
, ("List.++", "_L.append" ++ parens (s1 ++ "," ++ s2)) ]
ops = pow : map (\op -> (op, parens (s1 ++ op ++ s2))) ["+","-","*","/","&&","||"]
where pow = ("^" , "Math.pow(" ++ s1 ++ "," ++ s2 ++ ")")
basics = ops ++ map (\(op,e) -> ("Basics." ++ op, e))
(ops ++ [ ("<|", s1 ++ parens s2)
, ("|>", s2 ++ parens s1)
, ("==", "_N.eq(" ++ s1 ++ "," ++ s2 ++ ")")
, ("/=", "!_N.eq(" ++ s1 ++ "," ++ s2 ++ ")")
, ("<" , jsCompare s1 s2 "<0")
, (">" , jsCompare s1 s2 ">0")
, ("<=", jsCompare s1 s2 "<1")
, (">=", jsCompare s1 s2 ">-1")
, ("div", parens (s1 ++ "/" ++ s2 ++ "|0"))
])