Merge remote-tracking branch 'origin/master' into preludes-and-subclassing

semantic.cabal

@@ -72,6 +72,7 @@ library
                      , Data.Patch
                      , Data.Range
                      , Data.Record
+                     , Data.Semigroup.App
                      , Data.Source
                      , Data.Span
                      , Data.SplitDiff
@@ -211,6 +212,7 @@ test-suite test
   main-is:             Spec.hs
   other-modules:       Assigning.Assignment.Spec
                      , Analysis.Go.Spec
+                     , Analysis.PHP.Spec
                      , Analysis.Python.Spec
                      , Analysis.Ruby.Spec
                      , Analysis.TypeScript.Spec

src/Analysis/Abstract/Evaluating.hs

@@ -4,6 +4,8 @@ module Analysis.Abstract.Evaluating
 , evaluate
 , evaluates
 , evaluateWith
+, require
+, load
 ) where
 
 import Control.Abstract.Evaluator
@@ -13,6 +15,9 @@ import Control.Monad.Effect.Reader
 import Control.Monad.Effect.State
 import Data.Abstract.Configuration
 import qualified Data.Abstract.Environment as Env
+import Data.Abstract.Environment (Environment)
+import qualified Data.Abstract.Exports as Export
+import Data.Abstract.Exports (Exports)
 import Data.Abstract.Evaluatable
 import Data.Abstract.ModuleTable
 import Data.Abstract.Value
@@ -90,6 +95,46 @@ withModules Blob{..} pairs = localModuleTable (const moduleTable)
       _ ->  toName path
     toName str = qualifiedName (fmap BC.pack (splitWhen (== pathSeparator) str))
 
+-- | Require/import another module by name and return it's environment and value.
+--
+-- Looks up the term's name in the cache of evaluated modules first, returns if found, otherwise loads/evaluates the module.
+require :: (MonadAnalysis term value m, MonadValue value m)
+        => ModuleName
+        -> m (EnvironmentFor value, value)
+require name = getModuleTable >>= maybe (load name) pure . moduleTableLookup name
+
+-- | Load another module by name and return it's environment and value.
+--
+-- Always loads/evaluates.
+load :: (MonadAnalysis term value m, MonadValue value m)
+     => ModuleName
+     -> m (EnvironmentFor value, value)
+load name = askModuleTable >>= maybe notFound evalAndCache . moduleTableLookup name
+  where
+    notFound = fail ("cannot load module: " <> show name)
+    evalAndCache :: (MonadAnalysis term value m, MonadValue value m) => [term] -> m (EnvironmentFor value, value)
+    evalAndCache []     = (,) <$> pure mempty <*> unit
+    evalAndCache [x]    = evalAndCache' x
+    evalAndCache (x:xs) = do
+      (env, _) <- evalAndCache' x
+      (env', v') <- evalAndCache xs
+      pure (env <> env', v')
+
+    evalAndCache' :: (MonadAnalysis term value m) => term -> m (EnvironmentFor value, value)
+    evalAndCache' x = do
+      v <- evaluateModule x
+      env <- filterEnv <$> getExports <*> getEnv
+      modifyModuleTable (moduleTableInsert name (env, v))
+      pure (env, v)
+
+    -- TODO: If the set of exports is empty because no exports have been
+    -- defined, do we export all terms, or no terms? This behavior varies across
+    -- languages. We need better semantics rather than doing it ad-hoc.
+    filterEnv :: Exports l a -> Environment l a -> Environment l a
+    filterEnv ports env
+      | Export.null ports = env
+      | otherwise = Export.toEnvironment ports <> Env.overwrite (Export.aliases ports) env
+
 -- | An analysis evaluating @term@s to @value@s with a list of @effects@ using 'Evaluatable', and producing incremental results of type @a@.
 newtype Evaluating term value effects a = Evaluating (Eff effects a)
   deriving (Applicative, Functor, Effectful, Monad)
@@ -106,7 +151,7 @@ type EvaluatingEffects term value
      , State  (HeapFor value)                             -- The heap
      , Reader (ModuleTable [term])                        -- Cache of unevaluated modules
      , Reader (EnvironmentFor value)                      -- Default environment used by evaluateModule
-     , State  (ModuleTable (EnvironmentFor value)) -- Cache of evaluated modules
+     , State  (ModuleTable (EnvironmentFor value, value)) -- Cache of evaluated modules
      , State  (ExportsFor value)                          -- Exports (used to filter environments when they are imported)
      , State  (IntMap.IntMap term)                        -- For jumps
      ]
@@ -144,7 +189,7 @@ instance Member (State (HeapFor value)) effects => MonadHeap value (Evaluating t
   getHeap = raise get
   putHeap = raise . put
 
-instance Members '[Reader (ModuleTable [term]), State (ModuleTable (EnvironmentFor value))] effects => MonadModuleTable term value (Evaluating term value effects) where
+instance Members '[Reader (ModuleTable [term]), State (ModuleTable (EnvironmentFor value, value))] effects => MonadModuleTable term value (Evaluating term value effects) where
   getModuleTable = raise get
   putModuleTable = raise . put
 

src/Control/Abstract/Analysis.hs

@@ -3,8 +3,6 @@
 module Control.Abstract.Analysis
 ( MonadAnalysis(..)
 , evaluateTerm
-, require
-, load
 , liftAnalyze
 , runAnalysis
 , module X
@@ -20,14 +18,8 @@ import qualified Control.Monad.Effect as Effect
 import Control.Monad.Effect.Fail as X
 import Control.Monad.Effect.Reader as X
 import Control.Monad.Effect.State as X
-import Data.Abstract.Environment (Environment)
-import qualified Data.Abstract.Environment as Env
-import Data.Abstract.Exports (Exports)
-import qualified Data.Abstract.Exports as Export
-import Data.Abstract.ModuleTable
-import Data.Abstract.Value
 import Data.Coerce
-import Prelude hiding (fail)
+import Prelude
 import Prologue
 
 -- | A 'Monad' in which one can evaluate some specific term type to some specific value type.
@@ -54,44 +46,6 @@ class (MonadEvaluator term value m, Recursive term) => MonadAnalysis term value
 evaluateTerm :: MonadAnalysis term value m => term -> m value
 evaluateTerm = foldSubterms analyzeTerm
 
-
--- | Require/import another term/file and return an Effect.
---
--- Looks up the term's name in the cache of evaluated modules first, returns a value if found, otherwise loads/evaluates the module.
-require :: ( MonadAnalysis term value m
-           , Ord (LocationFor value)
-           )
-        => ModuleName
-        -> m (EnvironmentFor value)
-require name = getModuleTable >>= maybe (load name) pure . moduleTableLookup name
-
--- | Load another term/file and return an Effect.
---
--- Always loads/evaluates.
-load :: ( MonadAnalysis term value m
-        , Ord (LocationFor value)
-        )
-     => ModuleName
-     -> m (EnvironmentFor value)
-load name = askModuleTable >>= maybe notFound evalAndCache . moduleTableLookup name
-  where
-    notFound = fail ("cannot load module: " <> show name)
-    evalAndCache :: (MonadAnalysis term value m, Ord (LocationFor value)) => [term] -> m (EnvironmentFor value)
-    evalAndCache []     = pure mempty
-    evalAndCache (x:xs) = do
-      void $ evaluateModule x
-      env <- filterEnv <$> getExports <*> getEnv
-      modifyModuleTable (moduleTableInsert name env)
-      (env <>) <$> evalAndCache xs
-
-    -- TODO: If the set of exports is empty because no exports have been
-    -- defined, do we export all terms, or no terms? This behavior varies across
-    -- languages. We need better semantics rather than doing it ad-hoc.
-    filterEnv :: (Ord l) => Exports l a -> Environment l a -> Environment l a
-    filterEnv ports env
-      | Export.null ports = env
-      | otherwise = Export.toEnvironment ports <> Env.overwrite (Export.aliases ports) env
-
 -- | Lift a 'SubtermAlgebra' for an underlying analysis into a containing analysis. Use this when defining an analysis which can be composed onto other analyses to ensure that a call to 'analyzeTerm' occurs in the inner analysis and not the outer one.
 liftAnalyze :: ( Coercible (  m term value (effects :: [* -> *]) value) (t m term value effects value)
                , Coercible (t m term value effects value) (  m term value effects value)

src/Control/Abstract/Evaluator.hs

@@ -129,9 +129,9 @@ assign address = modifyHeap . heapInsert address
 -- | A 'Monad' abstracting tables of modules available for import.
 class Monad m => MonadModuleTable term value m | m -> term, m -> value where
   -- | Retrieve the table of evaluated modules.
-  getModuleTable :: m (ModuleTable (EnvironmentFor value))
+  getModuleTable :: m (ModuleTable (EnvironmentFor value, value))
   -- | Set the table of evaluated modules.
-  putModuleTable :: ModuleTable (EnvironmentFor value) -> m ()
+  putModuleTable :: ModuleTable (EnvironmentFor value, value) -> m ()
 
   -- | Retrieve the table of unevaluated modules.
   askModuleTable :: m (ModuleTable [term])
@@ -139,7 +139,7 @@ class Monad m => MonadModuleTable term value m | m -> term, m -> value where
   localModuleTable :: (ModuleTable [term] -> ModuleTable [term]) -> m a -> m a
 
 -- | Update the evaluated module table.
-modifyModuleTable :: MonadModuleTable term value m => (ModuleTable (EnvironmentFor value) -> ModuleTable (EnvironmentFor value)) -> m ()
+modifyModuleTable :: MonadModuleTable term value m => (ModuleTable (EnvironmentFor value, value) -> ModuleTable (EnvironmentFor value, value)) -> m ()
 modifyModuleTable f = do
   table <- getModuleTable
   putModuleTable $! f table

src/Control/Abstract/Value.hs

@@ -88,7 +88,7 @@ class (Monad m, Show value) => MonadValue value m where
 
   -- | Build a class value from a name and environment.
   klass :: Name                 -- ^ The new class's identifier
-        -> Maybe value          -- ^ A list of superclasses
+        -> Maybe value          -- ^ An optional superclass.
         -> EnvironmentFor value -- ^ The environment to capture
         -> m value
 
@@ -236,7 +236,6 @@ instance ( Monad m
     injValue . Closure names l . Env.bind (foldr Set.delete (freeVariables body) names) <$> getEnv
 
   apply op params
-    | Just klass@Class{} <- prjValue op = pure . injValue $ klass
     | Just (Closure names label env) <- prjValue op = do
       bindings <- foldr (\ (name, param) rest -> do
         v <- param

src/Data/Abstract/Evaluatable.hs

@@ -16,6 +16,7 @@ import Data.Abstract.Value
 import Data.Functor.Classes
 import Data.Proxy
 import Data.Semigroup.Foldable
+import Data.Semigroup.App
 import Data.Term
 import Prelude hiding (fail)
 import Prologue
@@ -51,14 +52,4 @@ instance Evaluatable s => Evaluatable (TermF s a) where
 --   3. Only the last statement’s return value is returned.
 instance Evaluatable [] where
   -- 'nonEmpty' and 'foldMap1' enable us to return the last statement’s result instead of 'unit' for non-empty lists.
-  eval = maybe unit (runImperative . foldMap1 (Imperative . subtermValue)) . nonEmpty
-
--- | A 'Semigroup' providing an imperative context which extends the local environment with new bindings.
-newtype Imperative m a = Imperative { runImperative :: m a }
-
-instance MonadEnvironment value m => Semigroup (Imperative m a) where
-  Imperative a <> Imperative b = Imperative (a *> b)
-
-instance (MonadEnvironment value m, MonadValue value m) => Monoid (Imperative m value) where
-  mempty = Imperative unit
-  mappend = (<>)
+  eval = maybe unit (runApp . foldMap1 (App . subtermValue)) . nonEmpty

src/Data/Abstract/FreeVariables.hs

@@ -5,7 +5,6 @@ import Prologue
 import Data.Term
 import Data.ByteString (intercalate)
 import qualified Data.List.NonEmpty as NonEmpty
-import Data.Abstract.Path
 
 -- | The type of variable names.
 type Name = NonEmpty ByteString
@@ -18,10 +17,6 @@ name x = x :| []
 qualifiedName :: [ByteString] -> Name
 qualifiedName = NonEmpty.fromList
 
--- | Construct a qualified 'Name' from a `/` delimited path.
-pathToQualifiedName :: ByteString -> Name
-pathToQualifiedName = qualifiedName . splitOnPathSeparator
-
 -- | User friendly 'ByteString' of a qualified 'Name'.
 friendlyName :: Name -> ByteString
 friendlyName xs = intercalate "." (NonEmpty.toList xs)

src/Data/Abstract/Path.hs

@@ -3,17 +3,12 @@ module Data.Abstract.Path where
 import Prologue
 import qualified Data.ByteString.Char8 as BC
 import qualified Data.ByteString as B
-import Data.Char (ord)
 
--- | Split a 'ByteString' path on `/`, stripping quotes and any `./` prefix.
 splitOnPathSeparator :: ByteString -> [ByteString]
-splitOnPathSeparator = splitOnPathSeparator' id
-
-splitOnPathSeparator' :: (ByteString -> ByteString) -> ByteString -> [ByteString]
-splitOnPathSeparator' f = BC.split '/' . f . dropRelativePrefix . stripQuotes
+splitOnPathSeparator = BC.split '/'
 
 stripQuotes :: ByteString -> ByteString
-stripQuotes = B.filter (/= fromIntegral (ord '\"'))
+stripQuotes = B.filter (`B.notElem` "\'\"")
 
 dropRelativePrefix :: ByteString -> ByteString
 dropRelativePrefix = BC.dropWhile (== '/') . BC.dropWhile (== '.')

src/Data/Semigroup/App.hs

@@ -0,0 +1,39 @@
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+module Data.Semigroup.App
+( App(..)
+, AppMerge(..)
+) where
+
+import Control.Applicative
+import Data.Semigroup
+
+-- $setup
+-- >>> import Test.QuickCheck
+-- >>> instance Arbitrary (f a) => Arbitrary (App f a) where arbitrary = App <$> arbitrary ; shrink = map App . shrink . runApp
+-- >>> instance Arbitrary (f a) => Arbitrary (AppMerge f a) where arbitrary = AppMerge <$> arbitrary ; shrink = map AppMerge . shrink . runAppMerge
+
+-- | 'Semigroup' under '*>'.
+newtype App f a = App { runApp :: f a }
+  deriving (Alternative, Applicative, Bounded, Enum, Eq, Foldable, Functor, Monad, Ord, Show, Traversable)
+
+-- $ Associativity:
+--   prop> \ a b c -> a <> (b <> c) == (a <> b) <> (c :: App Maybe Integer)
+instance Applicative f => Semigroup (App f a) where
+  App a <> App b = App (a *> b)
+
+
+-- | 'Semigroup' and 'Monoid' under '<*>' and '<>'.
+newtype AppMerge f a = AppMerge { runAppMerge :: f a }
+  deriving (Alternative, Applicative, Bounded, Enum, Eq, Foldable, Functor, Monad, Ord, Show, Traversable)
+
+-- $ Associativity:
+--   prop> \ a b c -> a <> (b <> c) == (a <> b) <> (c :: AppMerge Maybe String)
+instance (Applicative f, Semigroup a) => Semigroup (AppMerge f a) where
+  AppMerge a <> AppMerge b = AppMerge ((<>) <$> a <*> b)
+
+-- $ Identity:
+--   prop> \ a -> mempty <> a == (a :: AppMerge Maybe String)
+--   prop> \ a -> a <> mempty == (a :: AppMerge Maybe String)
+instance (Applicative f, Monoid a, Semigroup a) => Monoid (AppMerge f a) where
+  mempty = AppMerge (pure mempty)
+  mappend = (<>)

src/Data/Syntax/Declaration.hs

@@ -1,6 +1,7 @@
 {-# LANGUAGE DeriveAnyClass, MultiParamTypeClasses, ScopedTypeVariables, UndecidableInstances #-}
 module Data.Syntax.Declaration where
 
+import Analysis.Abstract.Evaluating
 import qualified Data.Abstract.Environment as Env
 import Data.Abstract.Evaluatable
 import Diffing.Algorithm
@@ -244,7 +245,7 @@ instance Show1 QualifiedExportFrom where liftShowsPrec = genericLiftShowsPrec
 instance Evaluatable QualifiedExportFrom where
   eval (QualifiedExportFrom from exportSymbols) = do
     let moduleName = freeVariable (subterm from)
-    importedEnv <- isolate (require moduleName)
+    (importedEnv, _) <- isolate (require moduleName)
     -- Look up addresses in importedEnv and insert the aliases with addresses into the exports.
     for_ exportSymbols $ \(name, alias) -> do
       let address = Env.lookup name importedEnv
@@ -277,7 +278,7 @@ instance Show1 QualifiedImport where liftShowsPrec = genericLiftShowsPrec
 
 instance Evaluatable QualifiedImport where
   eval (QualifiedImport from alias xs) = do
-    importedEnv <- isolate (require moduleName)
+    (importedEnv, _) <- isolate (require moduleName)
     modifyEnv (mappend (Env.overwrite (renames importedEnv) importedEnv))
     unit
     where
@@ -300,7 +301,7 @@ instance Show1 Import where liftShowsPrec = genericLiftShowsPrec
 
 instance Evaluatable Import where
   eval (Import from xs _) = do
-    importedEnv <- isolate (require moduleName)
+    (importedEnv, _) <- isolate (require moduleName)
     modifyEnv (mappend (renamed importedEnv))
     unit
     where

src/Language/Go/Assignment.hs

@@ -393,7 +393,7 @@ importDeclaration = makeTerm'' <$> symbol ImportDeclaration <*> children (manyTe
     namedImport = inj <$> (flip Declaration.QualifiedImport <$> packageIdentifier <*> importFromPath <*> pure [])
     -- `import "lib/Math"`
     plainImport = inj <$> (symbol InterpretedStringLiteral >>= \loc -> do
-      names <- splitOnPathSeparator <$> source
+      names <- toName <$> source
       let from = makeTerm loc (Syntax.Identifier (qualifiedName names))
       let alias = makeTerm loc (Syntax.Identifier (name (last names))) -- Go takes `import "lib/Math"` and uses `Math` as the qualified name (e.g. `Math.Sin()`)
       Declaration.QualifiedImport <$> pure from <*> pure alias <*> pure [])
@@ -403,7 +403,11 @@ importDeclaration = makeTerm'' <$> symbol ImportDeclaration <*> children (manyTe
     underscore = makeTerm <$> symbol BlankIdentifier <*> (Literal.TextElement <$> source)
     importSpec     = makeTerm' <$> symbol ImportSpec <*> children (sideEffectImport <|> dotImport <|> namedImport <|> plainImport)
     importSpecList = makeTerm <$> symbol ImportSpecList <*> children (manyTerm (importSpec <|> comment))
-    importFromPath = makeTerm <$> symbol InterpretedStringLiteral <*> (Syntax.Identifier <$> (pathToQualifiedName <$> source))
+    importFromPath = makeTerm <$> symbol InterpretedStringLiteral <*> (Syntax.Identifier <$> (toQualifiedName <$> source))
+
+    toQualifiedName = qualifiedName . toName
+    toName = splitOnPathSeparator . dropRelativePrefix . stripQuotes
+
 
 indexExpression :: Assignment
 indexExpression = makeTerm <$> symbol IndexExpression <*> children (Expression.Subscript <$> expression <*> manyTerm expression)

src/Language/PHP/Syntax.hs

@@ -1,393 +1,491 @@
 {-# LANGUAGE DeriveAnyClass #-}
 module Language.PHP.Syntax where
 
-import Prologue hiding (Text)
+import Analysis.Abstract.Evaluating
+import Data.Abstract.Evaluatable
+import Data.Abstract.Path
 import Diffing.Algorithm
+import Prologue hiding (Text)
+
 
 newtype Text a = Text ByteString
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Text where liftEq = genericLiftEq
 instance Ord1 Text where liftCompare = genericLiftCompare
 instance Show1 Text where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable Text
+
 
 newtype VariableName a = VariableName a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 VariableName where liftEq = genericLiftEq
 instance Ord1 VariableName where liftCompare = genericLiftCompare
 instance Show1 VariableName where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable VariableName
 
-newtype RequireOnce a = RequireOnce a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+-- TODO: Variables defined in an included file take on scope of the source line
+-- on which the inclusion occurs in the including file. However, functions and
+-- classes defined in the included file are always in global scope.
 
-instance Eq1 RequireOnce where liftEq = genericLiftEq
-instance Ord1 RequireOnce where liftCompare = genericLiftCompare
-instance Show1 RequireOnce where liftShowsPrec = genericLiftShowsPrec
+-- TODO: If inclusion occurs inside a function definition within the including
+-- file, the complete contents of the included file are treated as though it
+-- were defined inside that function.
+
+doInclude :: (MonadValue value m, MonadAnalysis term value m) => Subterm t (m value) -> m value
+doInclude path = do
+  name <- toQualifiedName <$> (subtermValue path >>= asString)
+  (importedEnv, v) <- isolate (load name)
+  modifyEnv (mappend importedEnv)
+  pure v
+
+doIncludeOnce :: (MonadValue value m, MonadAnalysis term value m) => Subterm t (m value) -> m value
+doIncludeOnce path = do
+  name <- toQualifiedName <$> (subtermValue path >>= asString)
+  (importedEnv, v) <- isolate (require name)
+  modifyEnv (mappend importedEnv)
+  pure v
+
+toQualifiedName :: ByteString -> Name
+toQualifiedName = qualifiedName . splitOnPathSeparator . dropExtension . dropRelativePrefix . stripQuotes
 
 newtype Require a = Require a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Require where liftEq          = genericLiftEq
 instance Ord1 Require where liftCompare    = genericLiftCompare
 instance Show1 Require where liftShowsPrec = genericLiftShowsPrec
 
+instance Evaluatable Require where
+  eval (Require path) = doInclude path
+
+
+newtype RequireOnce a = RequireOnce a
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+
+instance Eq1 RequireOnce where liftEq = genericLiftEq
+instance Ord1 RequireOnce where liftCompare = genericLiftCompare
+instance Show1 RequireOnce where liftShowsPrec = genericLiftShowsPrec
+
+instance Evaluatable RequireOnce where
+  eval (RequireOnce path) = doIncludeOnce path
+
+
 newtype Include a = Include a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Include where liftEq          = genericLiftEq
 instance Ord1 Include where liftCompare    = genericLiftCompare
 instance Show1 Include where liftShowsPrec = genericLiftShowsPrec
 
+instance Evaluatable Include where
+  eval (Include path) = doInclude path
+
+
 newtype IncludeOnce a = IncludeOnce a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 IncludeOnce where liftEq          = genericLiftEq
 instance Ord1 IncludeOnce where liftCompare    = genericLiftCompare
 instance Show1 IncludeOnce where liftShowsPrec = genericLiftShowsPrec
 
+instance Evaluatable IncludeOnce where
+  eval (IncludeOnce path) = doIncludeOnce path
+
+
 newtype ArrayElement a = ArrayElement a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ArrayElement where liftEq          = genericLiftEq
 instance Ord1 ArrayElement where liftCompare    = genericLiftCompare
 instance Show1 ArrayElement where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ArrayElement
 
 newtype GlobalDeclaration a = GlobalDeclaration [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 GlobalDeclaration where liftEq          = genericLiftEq
 instance Ord1 GlobalDeclaration where liftCompare    = genericLiftCompare
 instance Show1 GlobalDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable GlobalDeclaration
 
 newtype SimpleVariable a = SimpleVariable a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 SimpleVariable where liftEq          = genericLiftEq
 instance Ord1 SimpleVariable where liftCompare    = genericLiftCompare
 instance Show1 SimpleVariable where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable SimpleVariable
 
 
 -- | TODO: Unify with TypeScript's PredefinedType
 newtype CastType a = CastType { _castType :: ByteString }
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 CastType where liftEq = genericLiftEq
 instance Ord1 CastType where liftCompare = genericLiftCompare
 instance Show1 CastType where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable CastType
 
 newtype ErrorControl a = ErrorControl a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ErrorControl where liftEq = genericLiftEq
 instance Ord1 ErrorControl where liftCompare = genericLiftCompare
 instance Show1 ErrorControl where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ErrorControl
 
 newtype Clone a = Clone a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Clone where liftEq = genericLiftEq
 instance Ord1 Clone where liftCompare = genericLiftCompare
 instance Show1 Clone where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable Clone
 
 newtype ShellCommand a = ShellCommand ByteString
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ShellCommand where liftEq = genericLiftEq
 instance Ord1 ShellCommand where liftCompare = genericLiftCompare
 instance Show1 ShellCommand where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ShellCommand
 
 -- | TODO: Combine with TypeScript update expression.
 newtype Update a = Update { _updateSubject :: a }
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Update where liftEq = genericLiftEq
 instance Ord1 Update where liftCompare = genericLiftCompare
 instance Show1 Update where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable Update
 
 newtype NewVariable a = NewVariable [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 NewVariable where liftEq = genericLiftEq
 instance Ord1 NewVariable where liftCompare = genericLiftCompare
 instance Show1 NewVariable where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable NewVariable
 
 newtype RelativeScope a = RelativeScope ByteString
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 RelativeScope where liftEq = genericLiftEq
 instance Ord1 RelativeScope where liftCompare = genericLiftCompare
 instance Show1 RelativeScope where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable RelativeScope
 
 data QualifiedName a = QualifiedName a a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 QualifiedName where liftEq = genericLiftEq
 instance Ord1 QualifiedName where liftCompare = genericLiftCompare
 instance Show1 QualifiedName where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable QualifiedName
 
 newtype NamespaceName a = NamespaceName [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 NamespaceName where liftEq = genericLiftEq
 instance Ord1 NamespaceName where liftCompare = genericLiftCompare
 instance Show1 NamespaceName where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable NamespaceName
 
 newtype ConstDeclaration a = ConstDeclaration [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ConstDeclaration where liftEq = genericLiftEq
 instance Ord1 ConstDeclaration where liftCompare = genericLiftCompare
 instance Show1 ConstDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ConstDeclaration
 
 data ClassConstDeclaration a = ClassConstDeclaration a [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ClassConstDeclaration where liftEq = genericLiftEq
 instance Ord1 ClassConstDeclaration where liftCompare = genericLiftCompare
 instance Show1 ClassConstDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ClassConstDeclaration
 
 newtype ClassInterfaceClause a = ClassInterfaceClause [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ClassInterfaceClause where liftEq = genericLiftEq
 instance Ord1 ClassInterfaceClause where liftCompare = genericLiftCompare
 instance Show1 ClassInterfaceClause where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ClassInterfaceClause
 
 newtype ClassBaseClause a = ClassBaseClause a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ClassBaseClause where liftEq = genericLiftEq
 instance Ord1 ClassBaseClause where liftCompare = genericLiftCompare
 instance Show1 ClassBaseClause where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ClassBaseClause
+
 
 newtype UseClause a = UseClause [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 UseClause where liftEq = genericLiftEq
 instance Ord1 UseClause where liftCompare = genericLiftCompare
 instance Show1 UseClause where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable UseClause
 
 newtype ReturnType a = ReturnType a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ReturnType where liftEq = genericLiftEq
 instance Ord1 ReturnType where liftCompare = genericLiftCompare
 instance Show1 ReturnType where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ReturnType
 
 newtype TypeDeclaration a = TypeDeclaration a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 TypeDeclaration where liftEq = genericLiftEq
 instance Ord1 TypeDeclaration where liftCompare = genericLiftCompare
 instance Show1 TypeDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable TypeDeclaration
 
 newtype BaseTypeDeclaration a = BaseTypeDeclaration a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 BaseTypeDeclaration where liftEq = genericLiftEq
 instance Ord1 BaseTypeDeclaration where liftCompare = genericLiftCompare
 instance Show1 BaseTypeDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable BaseTypeDeclaration
 
 newtype ScalarType a = ScalarType ByteString
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ScalarType where liftEq = genericLiftEq
 instance Ord1 ScalarType where liftCompare = genericLiftCompare
 instance Show1 ScalarType where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ScalarType
 
 newtype EmptyIntrinsic a = EmptyIntrinsic a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 EmptyIntrinsic where liftEq = genericLiftEq
 instance Ord1 EmptyIntrinsic where liftCompare = genericLiftCompare
 instance Show1 EmptyIntrinsic where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable EmptyIntrinsic
 
 newtype ExitIntrinsic a = ExitIntrinsic a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ExitIntrinsic where liftEq = genericLiftEq
 instance Ord1 ExitIntrinsic where liftCompare = genericLiftCompare
 instance Show1 ExitIntrinsic where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ExitIntrinsic
 
 newtype IssetIntrinsic a = IssetIntrinsic a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 IssetIntrinsic where liftEq = genericLiftEq
 instance Ord1 IssetIntrinsic where liftCompare = genericLiftCompare
 instance Show1 IssetIntrinsic where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable IssetIntrinsic
 
 newtype EvalIntrinsic a = EvalIntrinsic a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 EvalIntrinsic where liftEq = genericLiftEq
 instance Ord1 EvalIntrinsic where liftCompare = genericLiftCompare
 instance Show1 EvalIntrinsic where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable EvalIntrinsic
 
 newtype PrintIntrinsic a = PrintIntrinsic a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 PrintIntrinsic where liftEq = genericLiftEq
 instance Ord1 PrintIntrinsic where liftCompare = genericLiftCompare
 instance Show1 PrintIntrinsic where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable PrintIntrinsic
 
 newtype NamespaceAliasingClause a = NamespaceAliasingClause a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 NamespaceAliasingClause where liftEq = genericLiftEq
 instance Ord1 NamespaceAliasingClause where liftCompare = genericLiftCompare
 instance Show1 NamespaceAliasingClause where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable NamespaceAliasingClause
 
 newtype NamespaceUseDeclaration a = NamespaceUseDeclaration [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 NamespaceUseDeclaration where liftEq = genericLiftEq
 instance Ord1 NamespaceUseDeclaration where liftCompare = genericLiftCompare
 instance Show1 NamespaceUseDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable NamespaceUseDeclaration
 
 newtype NamespaceUseClause a = NamespaceUseClause [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 NamespaceUseClause where liftEq = genericLiftEq
 instance Ord1 NamespaceUseClause where liftCompare = genericLiftCompare
 instance Show1 NamespaceUseClause where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable NamespaceUseClause
 
 newtype NamespaceUseGroupClause a = NamespaceUseGroupClause [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 NamespaceUseGroupClause where liftEq = genericLiftEq
 instance Ord1 NamespaceUseGroupClause where liftCompare = genericLiftCompare
 instance Show1 NamespaceUseGroupClause where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable NamespaceUseGroupClause
 
 data Namespace a = Namespace { namespaceName :: a, namespaceBody :: a}
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Namespace where liftEq = genericLiftEq
 instance Ord1 Namespace where liftCompare = genericLiftCompare
 instance Show1 Namespace where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable Namespace
 
 data TraitDeclaration a = TraitDeclaration { traitName :: a, traitStatements :: [a] }
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 TraitDeclaration where liftEq = genericLiftEq
 instance Ord1 TraitDeclaration where liftCompare = genericLiftCompare
 instance Show1 TraitDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable TraitDeclaration
 
 data AliasAs a = AliasAs { aliasAsName  :: a, aliasAsModifier :: a, aliasAsClause :: a }
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 AliasAs where liftEq = genericLiftEq
 instance Ord1 AliasAs where liftCompare = genericLiftCompare
 instance Show1 AliasAs where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable AliasAs
 
 data InsteadOf a = InsteadOf a a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 InsteadOf where liftEq = genericLiftEq
 instance Ord1 InsteadOf where liftCompare = genericLiftCompare
 instance Show1 InsteadOf where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable InsteadOf
 
 newtype TraitUseSpecification a = TraitUseSpecification [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 TraitUseSpecification where liftEq = genericLiftEq
 instance Ord1 TraitUseSpecification where liftCompare = genericLiftCompare
 instance Show1 TraitUseSpecification where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable TraitUseSpecification
 
 data TraitUseClause a = TraitUseClause [a] a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 TraitUseClause where liftEq = genericLiftEq
 instance Ord1 TraitUseClause where liftCompare = genericLiftCompare
 instance Show1 TraitUseClause where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable TraitUseClause
 
 data DestructorDeclaration a = DestructorDeclaration [a] a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 DestructorDeclaration where liftEq = genericLiftEq
 instance Ord1 DestructorDeclaration where liftCompare = genericLiftCompare
 instance Show1 DestructorDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable DestructorDeclaration
 
 newtype Static a = Static ByteString
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Static where liftEq = genericLiftEq
 instance Ord1 Static where liftCompare = genericLiftCompare
 instance Show1 Static where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable Static
 
 newtype ClassModifier a = ClassModifier ByteString
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ClassModifier where liftEq = genericLiftEq
 instance Ord1 ClassModifier where liftCompare = genericLiftCompare
 instance Show1 ClassModifier where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ClassModifier
 
 data ConstructorDeclaration a = ConstructorDeclaration [a] [a] a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 ConstructorDeclaration where liftEq = genericLiftEq
 instance Ord1 ConstructorDeclaration where liftCompare = genericLiftCompare
 instance Show1 ConstructorDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable ConstructorDeclaration
 
 data PropertyDeclaration a = PropertyDeclaration a [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 PropertyDeclaration where liftEq = genericLiftEq
 instance Ord1 PropertyDeclaration where liftCompare = genericLiftCompare
 instance Show1 PropertyDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable PropertyDeclaration
 
 data PropertyModifier a = PropertyModifier a a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 PropertyModifier where liftEq = genericLiftEq
 instance Ord1 PropertyModifier where liftCompare = genericLiftCompare
 instance Show1 PropertyModifier where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable PropertyModifier
 
 data InterfaceDeclaration a = InterfaceDeclaration a a [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 InterfaceDeclaration where liftEq = genericLiftEq
 instance Ord1 InterfaceDeclaration where liftCompare = genericLiftCompare
 instance Show1 InterfaceDeclaration where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable InterfaceDeclaration
 
 newtype InterfaceBaseClause a = InterfaceBaseClause [a]
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 InterfaceBaseClause where liftEq = genericLiftEq
 instance Ord1 InterfaceBaseClause where liftCompare = genericLiftCompare
 instance Show1 InterfaceBaseClause where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable InterfaceBaseClause
 
 newtype Echo a = Echo a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Echo where liftEq = genericLiftEq
 instance Ord1 Echo where liftCompare = genericLiftCompare
 instance Show1 Echo where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable Echo
 
 newtype Unset a = Unset a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Unset where liftEq = genericLiftEq
 instance Ord1 Unset where liftCompare = genericLiftCompare
 instance Show1 Unset where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable Unset
 
 data Declare a = Declare a a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 Declare where liftEq = genericLiftEq
 instance Ord1 Declare where liftCompare = genericLiftCompare
 instance Show1 Declare where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable Declare
 
 newtype DeclareDirective a = DeclareDirective a
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 DeclareDirective where liftEq = genericLiftEq
 instance Ord1 DeclareDirective where liftCompare = genericLiftCompare
 instance Show1 DeclareDirective where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable DeclareDirective
 
 newtype LabeledStatement a = LabeledStatement { _labeledStatementIdentifier :: a }
-  deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
+  deriving (Diffable, Eq, Foldable, Functor, FreeVariables1, GAlign, Generic1, Mergeable, Ord, Show, Traversable)
 
 instance Eq1 LabeledStatement where liftEq = genericLiftEq
 instance Ord1 LabeledStatement where liftCompare = genericLiftCompare
 instance Show1 LabeledStatement where liftShowsPrec = genericLiftShowsPrec
+instance Evaluatable LabeledStatement

src/Language/Ruby/Syntax.hs

@@ -1,11 +1,13 @@
 {-# LANGUAGE DeriveAnyClass #-}
 module Language.Ruby.Syntax where
 
+import Analysis.Abstract.Evaluating
 import Control.Monad (unless)
 import Control.Abstract.Value (MonadValue)
 import Data.Abstract.Evaluatable
+import Data.Abstract.ModuleTable
 import Data.Abstract.Path
-import Data.Abstract.Value (LocationFor)
+import Data.Abstract.Value (EnvironmentFor)
 import Diffing.Algorithm
 import Prelude hiding (fail)
 import Prologue
@@ -19,10 +21,22 @@ instance Show1 Require where liftShowsPrec = genericLiftShowsPrec
 
 instance Evaluatable Require where
   eval (Require _ x) = do
-    name <- pathToQualifiedName <$> (subtermValue x >>= asString)
-    importedEnv <- isolate (require name)
+    name <- toName <$> (subtermValue x >>= asString)
+    (importedEnv, v) <- isolate (doRequire name)
     modifyEnv (mappend importedEnv)
-    unit
+    pure v -- Returns True if the file was loaded, False if it was already loaded. http://ruby-doc.org/core-2.5.0/Kernel.html#method-i-require
+    where
+      toName = qualifiedName . splitOnPathSeparator . dropRelativePrefix . stripQuotes
+
+doRequire :: (MonadAnalysis term value m, MonadValue value m)
+          => ModuleName
+          -> m (EnvironmentFor value, value)
+doRequire name = do
+  moduleTable <- getModuleTable
+  case moduleTableLookup name moduleTable of
+    Nothing -> (,) <$> (fst <$> load name) <*> boolean True
+    Just (env, _) -> (,) <$> pure env <*> boolean False
+
 
 newtype Load a = Load { loadArgs :: [a] }
   deriving (Diffable, Eq, Foldable, Functor, GAlign, Generic1, Mergeable, Ord, Show, Traversable, FreeVariables1)
@@ -41,12 +55,12 @@ instance Evaluatable Load where
     doLoad path shouldWrap
   eval (Load _) = fail "invalid argument supplied to load, path is required"
 
-doLoad :: (MonadAnalysis term value m, MonadValue value m, Ord (LocationFor value)) => ByteString -> Bool -> m value
+doLoad :: (MonadAnalysis term value m, MonadValue value m) => ByteString -> Bool -> m value
 doLoad path shouldWrap = do
-  let name = pathToQualifiedName path
-  importedEnv <- isolate (load name)
+  (importedEnv, _) <- isolate (load (toName path))
   unless shouldWrap $ modifyEnv (mappend importedEnv)
-  unit
-  where pathToQualifiedName = qualifiedName . splitOnPathSeparator' dropExtension
+  boolean Prelude.True -- load always returns true. http://ruby-doc.org/core-2.5.0/Kernel.html#method-i-load
+  where
+    toName = qualifiedName . splitOnPathSeparator . dropExtension . dropRelativePrefix . stripQuotes
 
 -- TODO: autoload

src/Language/TypeScript/Assignment.hs

@@ -9,6 +9,7 @@ module Language.TypeScript.Assignment
 import Assigning.Assignment hiding (Assignment, Error)
 import qualified Assigning.Assignment as Assignment
 import Data.Abstract.FreeVariables
+import Data.Abstract.Path
 import Data.Record
 import Data.Syntax (emptyTerm, handleError, parseError, infixContext, makeTerm, makeTerm', makeTerm'', makeTerm1, contextualize, postContextualize)
 import qualified Data.Syntax as Syntax
@@ -672,7 +673,9 @@ importStatement =   makeImportTerm <$> symbol Grammar.ImportStatement <*> childr
     makeNameAliasPair from Nothing = (from, from)
 
 fromClause :: Assignment
-fromClause = makeTerm <$> symbol Grammar.String <*> (Syntax.Identifier <$> (pathToQualifiedName <$> source))
+fromClause = makeTerm <$> symbol Grammar.String <*> (Syntax.Identifier <$> (toName <$> source))
+  where
+    toName = qualifiedName . splitOnPathSeparator . dropRelativePrefix . stripQuotes
 
 debuggerStatement :: Assignment
 debuggerStatement = makeTerm <$> symbol Grammar.DebuggerStatement <*> (TypeScript.Syntax.Debugger <$ source)

src/Semantic/Util.hs

@@ -50,6 +50,10 @@ typecheckPythonFile path = runAnalysis @(Caching Evaluating Python.Term Type) .
 tracePythonFile path = runAnalysis @(Tracing [] Evaluating Python.Term Value) . evaluateModule . snd <$> parseFile pythonParser path
 evaluateDeadTracePythonFile path = runAnalysis @(DeadCode (Tracing [] Evaluating) Python.Term Value) . evaluateModule . snd <$> parseFile pythonParser path
 
+-- PHP
+evaluatePHPFile = evaluateFile phpParser
+evaluatePHPFiles = evaluateFiles phpParser
+
 -- TypeScript
 typecheckTypeScriptFile path = runAnalysis @(Caching Evaluating TypeScript.Term Type) . evaluateModule . snd <$> parseFile typescriptParser path
 evaluateTypeScriptFile = evaluateFile typescriptParser

test/Analysis/Go/Spec.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE OverloadedLists, TypeApplications #-}
+{-# LANGUAGE OverloadedLists #-}
 module Analysis.Go.Spec (spec) where
 
 import Data.Abstract.Value

test/Analysis/PHP/Spec.hs

@@ -0,0 +1,33 @@
+{-# LANGUAGE OverloadedLists #-}
+module Analysis.PHP.Spec (spec) where
+
+import Data.Abstract.Value
+import Data.Map
+
+import SpecHelpers
+
+
+spec :: Spec
+spec = parallel $ do
+  describe "evalutes PHP" $ do
+    it "include and require" $ do
+      env <- evaluate "main.php"
+      let expectedEnv = [ (qualifiedName ["foo"], addr 0)
+                        , (qualifiedName ["bar"], addr 1) ]
+      env `shouldBe` expectedEnv
+
+    it "include_once and require_once" $ do
+      env <- evaluate "main_once.php"
+      let expectedEnv = [ (qualifiedName ["foo"], addr 0)
+                        , (qualifiedName ["bar"], addr 1) ]
+      env `shouldBe` expectedEnv
+
+  where
+    addr = Address . Precise
+    fixtures = "test/fixtures/php/analysis/"
+    evaluate entry = snd . fst . fst . fst . fst <$>
+      evaluateFiles phpParser
+      [ fixtures <> entry
+      , fixtures <> "foo.php"
+      , fixtures <> "bar.php"
+      ]

test/Analysis/Ruby/Spec.hs

@@ -26,6 +26,10 @@ spec = parallel $ do
       fst res `shouldBe` Left "free variable: \"foo\""
       snd res `shouldBe` []
 
+    it "subclass" $ do
+      res <- evaluate' "subclass.rb"
+      fst res `shouldBe` Right (injValue (String "\"<bar>\""))
+
   where
     addr = Address . Precise
     fixtures = "test/fixtures/ruby/analysis/"

test/Spec.hs

@@ -1,6 +1,7 @@
 module Main where
 
 import qualified Analysis.Go.Spec
+import qualified Analysis.PHP.Spec
 import qualified Analysis.Python.Spec
 import qualified Analysis.Ruby.Spec
 import qualified Analysis.TypeScript.Spec
@@ -27,6 +28,7 @@ main = hspec $ do
   describe "Semantic.Stat" Semantic.Stat.Spec.spec
   parallel $ do
     describe "Analysis.Go" Analysis.Go.Spec.spec
+    describe "Analysis.PHP" Analysis.PHP.Spec.spec
     describe "Analysis.Python" Analysis.Python.Spec.spec
     describe "Analysis.Ruby" Analysis.Ruby.Spec.spec
     describe "Analysis.TypeScript" Analysis.TypeScript.Spec.spec

test/fixtures/php/analysis/bar.php

@@ -0,0 +1,4 @@
+<?php
+function bar() {
+  return 1;
+}

test/fixtures/php/analysis/foo.php

@@ -0,0 +1,4 @@
+<?php
+function foo() {
+  return 1;
+}

test/fixtures/php/analysis/main.php

@@ -0,0 +1,6 @@
+<?php
+include 'foo.php';
+require 'bar.php';
+
+foo();
+bar();

test/fixtures/php/analysis/main_once.php

@@ -0,0 +1,6 @@
+<?php
+include_once 'foo.php';
+require_once 'bar.php';
+
+foo();
+bar();

test/fixtures/ruby/analysis/subclass.rb

@@ -0,0 +1,13 @@
+class Foo
+  def inspect
+    "<foo>"
+  end
+end
+
+class Bar < Foo
+  def inspect
+    "<bar>"
+  end
+end
+
+Bar.inspect()