module Language.PureScript.CodeGen.JS (
module AST,
declToJs,
moduleToJs
) where
import Data.Maybe (fromMaybe, mapMaybe)
import Data.List (sortBy)
import Data.Function (on)
import Control.Arrow (second)
import Control.Monad (replicateM, forM)
import qualified Data.Map as M
import Language.PureScript.TypeChecker (Environment(..), NameKind(..))
import Language.PureScript.Values
import Language.PureScript.Names
import Language.PureScript.Scope
import Language.PureScript.Declarations
import Language.PureScript.Pretty.Common
import Language.PureScript.CodeGen.Monad
import Language.PureScript.Options
import Language.PureScript.CodeGen.JS.AST as AST
import Language.PureScript.Types
import Language.PureScript.CodeGen.Optimize
import Language.PureScript.CodeGen.Common (identToJs)
import Language.PureScript.TypeChecker.Monad (canonicalizeDataConstructor)
moduleToJs :: Options -> Module -> Environment -> [JS]
moduleToJs opts (Module pname@(ProperName name) decls) env =
[ JSVariableIntroduction name Nothing
, JSApp (JSFunction Nothing [name]
(JSBlock (concat $ mapMaybe (\decl -> fmap (map $ optimize opts) $ declToJs opts (ModuleName pname) decl env) (decls))))
[JSAssignment (JSVar name)
(JSBinary Or (JSVar name) (JSObjectLiteral []))]
]
declToJs :: Options -> ModuleName -> Declaration -> Environment -> Maybe [JS]
declToJs opts mp (ValueDeclaration ident _ _ val) e =
Just $ JSVariableIntroduction (identToJs ident) (Just (valueToJs opts mp e val))
: setProperty ident (var ident) mp
declToJs opts mp (BindingGroupDeclaration vals) e =
Just $ concatMap (\(ident, val) ->
JSVariableIntroduction (identToJs ident) (Just (valueToJs opts mp e val))
: setProperty ident (var ident) mp
) vals
declToJs _ mp (DataDeclaration _ _ ctors) _ =
Just $ flip concatMap ctors $ \(pn@(ProperName ctor), maybeTy) ->
let
ctorJs =
case maybeTy of
Nothing -> JSVariableIntroduction ctor (Just (JSObjectLiteral [ ("ctor", JSStringLiteral (show (Qualified (Just mp) pn))) ]))
Just _ -> JSFunction (Just ctor) ["value"]
(JSBlock [JSReturn
(JSObjectLiteral [ ("ctor", JSStringLiteral (show (Qualified (Just mp) pn)))
, ("value", JSVar "value") ])])
in ctorJs : setProperty (Escaped ctor) (JSVar ctor) mp
declToJs opts mp (DataBindingGroupDeclaration ds) e =
Just $ concat $ mapMaybe (flip (declToJs opts mp) e) ds
declToJs _ mp (ExternDeclaration importTy ident (Just js) _) _ =
Just $ js : setProperty ident (var ident) mp
declToJs _ _ _ _ = Nothing
setProperty :: Ident -> JS -> ModuleName -> [JS]
setProperty ident@(Op op) val (ModuleName (ProperName moduleName)) =
[ JSAssignment (JSAccessor (identToJs ident) (JSVar moduleName)) val
, JSAssignment (JSIndexer (JSStringLiteral op) (JSVar moduleName)) (JSAccessor (identToJs ident) (JSVar moduleName)) ]
setProperty ident val (ModuleName (ProperName moduleName)) =
[ JSAssignment (JSAccessor (identToJs ident) (JSVar moduleName)) val ]
var :: Ident -> JS
var = JSVar . identToJs
valueToJs :: Options -> ModuleName -> Environment -> Value -> JS
valueToJs _ _ _ (NumericLiteral n) = JSNumericLiteral n
valueToJs _ _ _ (StringLiteral s) = JSStringLiteral s
valueToJs _ _ _ (BooleanLiteral b) = JSBooleanLiteral b
valueToJs opts m e (ArrayLiteral xs) = JSArrayLiteral (map (valueToJs opts m e) xs)
valueToJs opts m e (ObjectLiteral ps) = JSObjectLiteral (map (second (valueToJs opts m e)) ps)
valueToJs opts m e (ObjectUpdate o ps) = JSApp (JSAccessor "extend" (JSVar "Object")) [ valueToJs opts m e o, JSObjectLiteral (map (second (valueToJs opts m e)) ps)]
valueToJs _ m e (Constructor (Qualified Nothing name)) =
case M.lookup (m, name) (dataConstructors e) of
Just (_, Alias aliasModule aliasIdent) -> qualifiedToJS identToJs (Qualified (Just aliasModule) aliasIdent)
_ -> JSVar . runProperName $ name
valueToJs _ _ _ (Constructor name) = qualifiedToJS runProperName name
valueToJs opts m e (Block sts) = JSApp (JSFunction Nothing [] (JSBlock (map (statementToJs opts m e) sts))) []
valueToJs opts m e (Case values binders) = bindersToJs opts m e binders (map (valueToJs opts m e) values)
valueToJs opts m e (IfThenElse cond th el) = JSConditional (valueToJs opts m e cond) (valueToJs opts m e th) (valueToJs opts m e el)
valueToJs opts m e (Accessor prop val) = JSAccessor prop (valueToJs opts m e val)
valueToJs opts m e (App val arg) = JSApp (valueToJs opts m e val) [valueToJs opts m e arg]
valueToJs opts m e (Abs arg val) = JSFunction Nothing [identToJs arg] (JSBlock [JSReturn (valueToJs opts m e val)])
valueToJs opts m e (TypedValue _ (Abs arg val) ty) | optionsPerformRuntimeTypeChecks opts = let arg' = identToJs arg in JSFunction Nothing [arg'] (JSBlock $ runtimeTypeChecks arg' ty ++ [JSReturn (valueToJs opts m e val)])
valueToJs _ m e (Var ident) = varToJs m e ident
valueToJs opts m e (TypedValue _ val _) = valueToJs opts m e val
valueToJs _ _ _ (TypeClassDictionary _ _) = error "Type class dictionary was not replaced"
valueToJs _ _ _ _ = error "Invalid argument to valueToJs"
runtimeTypeChecks :: String -> Type -> [JS]
runtimeTypeChecks arg ty =
let
argTy = getFunctionArgumentType ty
in
maybe [] (argumentCheck (JSVar arg)) argTy
where
getFunctionArgumentType :: Type -> Maybe Type
getFunctionArgumentType (TypeApp (TypeApp t funArg) _) | t == tyFunction = Just funArg
getFunctionArgumentType (ForAll _ ty' _) = getFunctionArgumentType ty'
getFunctionArgumentType _ = Nothing
argumentCheck :: JS -> Type -> [JS]
argumentCheck val t | t == tyNumber = [typeCheck val "number"]
argumentCheck val t | t == tyString = [typeCheck val "string"]
argumentCheck val t | t == tyBoolean = [typeCheck val "boolean"]
argumentCheck val (TypeApp t _) | t == tyArray = [arrayCheck val]
argumentCheck val (Object row) =
let
(pairs, _) = rowToList row
in
typeCheck val "object" : concatMap (\(prop, ty') -> argumentCheck (JSAccessor prop val) ty') pairs
argumentCheck val (TypeApp (TypeApp t _) _) | t == tyFunction = [typeCheck val "function"]
argumentCheck val (ForAll _ ty' _) = argumentCheck val ty'
argumentCheck _ _ = []
typeCheck :: JS -> String -> JS
typeCheck js ty' = JSIfElse (JSBinary NotEqualTo (JSTypeOf js) (JSStringLiteral ty')) (JSBlock [JSThrow (JSStringLiteral $ ty' ++ " expected")]) Nothing
arrayCheck :: JS -> JS
arrayCheck js = JSIfElse (JSUnary Not (JSApp (JSAccessor "isArray" (JSVar "Array")) [js])) (JSBlock [JSThrow (JSStringLiteral "Array expected")]) Nothing
varToJs :: ModuleName -> Environment -> Qualified Ident -> JS
varToJs m e qual@(Qualified _ ident) = go qual
where
go qual = case M.lookup (qualify m qual) (names e) of
Just (_, ty) | isExtern ty -> var ident
Just (_, Alias aliasModule aliasIdent) -> go (Qualified (Just aliasModule) aliasIdent)
_ -> case qual of
Qualified Nothing _ -> var ident
Qualified (Just (ModuleName (ProperName mn))) (Op op) -> JSIndexer (JSStringLiteral op) (JSVar mn)
_ -> qualifiedToJS identToJs qual
isExtern (Extern ForeignImport) = True
isExtern (Alias m' ident') = case M.lookup (m', ident') (names e) of
Just (_, ty') -> isExtern ty'
Nothing -> error "Undefined alias in varToJs"
isExtern _ = False
qualifiedToJS :: (a -> String) -> Qualified a -> JS
qualifiedToJS f (Qualified (Just (ModuleName (ProperName m))) a) = JSAccessor (f a) (JSVar m)
qualifiedToJS f (Qualified Nothing a) = JSVar (f a)
bindersToJs :: Options -> ModuleName -> Environment -> [([Binder], Maybe Guard, Value)] -> [JS] -> JS
bindersToJs opts m e binders vals = runGen (map identToJs (unusedNames (binders, vals))) $ do
valNames <- replicateM (length vals) fresh
jss <- forM binders $ \(bs, grd, result) -> go valNames [JSReturn (valueToJs opts m e result)] bs grd
return $ JSApp (JSFunction Nothing valNames (JSBlock (concat jss ++ [JSThrow (JSStringLiteral "Failed pattern match")])))
vals
where
go :: [String] -> [JS] -> [Binder] -> Maybe Guard -> Gen [JS]
go _ done [] Nothing = return done
go _ done [] (Just cond) = return [JSIfElse (valueToJs opts m e cond) (JSBlock done) Nothing]
go (v:vs) done' (b:bs) grd = do
done'' <- go vs done' bs grd
binderToJs m e v done'' b
go _ _ _ _ = error "Invalid arguments to bindersToJs"
binderToJs :: ModuleName -> Environment -> String -> [JS] -> Binder -> Gen [JS]
binderToJs _ _ _ done NullBinder = return done
binderToJs _ _ varName done (StringBinder str) =
return [JSIfElse (JSBinary EqualTo (JSVar varName) (JSStringLiteral str)) (JSBlock done) Nothing]
binderToJs _ _ varName done (NumberBinder num) =
return [JSIfElse (JSBinary EqualTo (JSVar varName) (JSNumericLiteral num)) (JSBlock done) Nothing]
binderToJs _ _ varName done (BooleanBinder True) =
return [JSIfElse (JSVar varName) (JSBlock done) Nothing]
binderToJs _ _ varName done (BooleanBinder False) =
return [JSIfElse (JSUnary Not (JSVar varName)) (JSBlock done) Nothing]
binderToJs _ _ varName done (VarBinder ident) =
return (JSVariableIntroduction (identToJs ident) (Just (JSVar varName)) : done)
binderToJs m e varName done (NullaryBinder ctor) =
if isOnlyConstructor m e ctor
then
return done
else
return [JSIfElse (JSBinary EqualTo (JSAccessor "ctor" (JSVar varName)) (JSStringLiteral (show ((\(mp, nm) -> Qualified (Just mp) nm) $ canonicalizeDataConstructor m e ctor)))) (JSBlock done) Nothing]
binderToJs m e varName done (UnaryBinder ctor b) = do
value <- fresh
js <- binderToJs m e value done b
let success = JSBlock (JSVariableIntroduction value (Just (JSAccessor "value" (JSVar varName))) : js)
if isOnlyConstructor m e ctor
then
return [success]
else
return [JSIfElse (JSBinary EqualTo (JSAccessor "ctor" (JSVar varName)) (JSStringLiteral (show ((\(mp, nm) -> Qualified (Just mp) nm) $ canonicalizeDataConstructor m e ctor))))
success
Nothing]
binderToJs m e varName done (ObjectBinder bs) = go done bs
where
go :: [JS] -> [(String, Binder)] -> Gen [JS]
go done' [] = return done'
go done' ((prop, binder):bs') = do
propVar <- fresh
done'' <- go done' bs'
js <- binderToJs m e propVar done'' binder
return (JSVariableIntroduction propVar (Just (JSAccessor prop (JSVar varName))) : js)
binderToJs m e varName done (ArrayBinder bs) = do
js <- go done 0 bs
return [JSIfElse (JSBinary EqualTo (JSAccessor "length" (JSVar varName)) (JSNumericLiteral (Left (fromIntegral $ length bs)))) (JSBlock js) Nothing]
where
go :: [JS] -> Integer -> [Binder] -> Gen [JS]
go done' _ [] = return done'
go done' index (binder:bs') = do
elVar <- fresh
done'' <- go done' (index + 1) bs'
js <- binderToJs m e elVar done'' binder
return (JSVariableIntroduction elVar (Just (JSIndexer (JSNumericLiteral (Left index)) (JSVar varName))) : js)
binderToJs m e varName done (ConsBinder headBinder tailBinder) = do
headVar <- fresh
tailVar <- fresh
js1 <- binderToJs m e headVar done headBinder
js2 <- binderToJs m e tailVar js1 tailBinder
return [JSIfElse (JSBinary GreaterThan (JSAccessor "length" (JSVar varName)) (JSNumericLiteral (Left 0))) (JSBlock
( JSVariableIntroduction headVar (Just (JSIndexer (JSNumericLiteral (Left 0)) (JSVar varName))) :
JSVariableIntroduction tailVar (Just (JSApp (JSAccessor "slice" (JSVar varName)) [JSNumericLiteral (Left 1)])) :
js2
)) Nothing]
binderToJs m e varName done (NamedBinder ident binder) = do
js <- binderToJs m e varName done binder
return (JSVariableIntroduction (identToJs ident) (Just (JSVar varName)) : js)
isOnlyConstructor :: ModuleName -> Environment -> Qualified ProperName -> Bool
isOnlyConstructor m e ctor =
let (ty, _) = fromMaybe (error "Data constructor not found") $ qualify m ctor `M.lookup` dataConstructors e
in numConstructors ty == 1
where
numConstructors ty = length $ filter (\(ty1, _) -> ((==) `on` typeConstructor) ty ty1) $ M.elems $ dataConstructors e
typeConstructor (TypeConstructor qual) = qualify m qual
typeConstructor (ForAll _ ty _) = typeConstructor ty
typeConstructor (TypeApp (TypeApp t _) ty) | t == tyFunction = typeConstructor ty
typeConstructor (TypeApp ty _) = typeConstructor ty
typeConstructor fn = error $ "Invalid arguments to typeConstructor: " ++ show fn
statementToJs :: Options -> ModuleName -> Environment -> Statement -> JS
statementToJs opts m e (VariableIntroduction ident value) = JSVariableIntroduction (identToJs ident) (Just (valueToJs opts m e value))
statementToJs opts m e (Assignment target value) = JSAssignment (JSVar (identToJs target)) (valueToJs opts m e value)
statementToJs opts m e (While cond sts) = JSWhile (valueToJs opts m e cond) (JSBlock (map (statementToJs opts m e) sts))
statementToJs opts m e (For ident start end sts) = JSFor (identToJs ident) (valueToJs opts m e start) (valueToJs opts m e end) (JSBlock (map (statementToJs opts m e) sts))
statementToJs opts m e (If ifst) = ifToJs ifst
where
ifToJs :: IfStatement -> JS
ifToJs (IfStatement cond thens elses) = JSIfElse (valueToJs opts m e cond) (JSBlock (map (statementToJs opts m e) thens)) (fmap elseToJs elses)
elseToJs :: ElseStatement -> JS
elseToJs (Else sts) = JSBlock (map (statementToJs opts m e) sts)
elseToJs (ElseIf elif) = ifToJs elif
statementToJs opts m e (Return value) = JSReturn (valueToJs opts m e value)