Add array assignment to the IR

lib/Language/Elna/Frontend/AST.hs

@@ -176,16 +176,16 @@ instance Show Expression
     show (DivisionExpression lhs rhs) = concat [show lhs, " / ", show rhs]
     show (VariableExpression variable) = show variable
 
-newtype VariableAccess
+data VariableAccess
     = VariableAccess Identifier
-    -- | ArrayAccess VariableAccess Expression
+    | ArrayAccess VariableAccess Expression
     deriving Eq
 
 instance Show VariableAccess
   where
     show (VariableAccess variableName) = show variableName
-    {- show (ArrayAccess arrayAccess elementIndex) =
-        concat [show arrayAccess, "[", show elementIndex, "]"] -}
+    show (ArrayAccess arrayAccess elementIndex) =
+        concat [show arrayAccess, "[", show elementIndex, "]"]
 
 data Condition
     = EqualCondition Expression Expression

lib/Language/Elna/Frontend/NameAnalysis.hs

@@ -202,18 +202,6 @@ condition globalTable (AST.GreaterOrEqualCondition lhs rhs)
 variableAccess :: SymbolTable -> AST.VariableAccess -> NameAnalysis ()
 variableAccess globalTable (AST.VariableAccess identifier) =
     checkSymbol globalTable identifier
-{- variableAccess globalTable (AST.ArrayAccess arrayExpression indexExpression)
+variableAccess globalTable (AST.ArrayAccess arrayExpression indexExpression)
     = variableAccess globalTable arrayExpression
     >> expression globalTable indexExpression
-
-enter :: Identifier -> Info -> SymbolTable -> NameAnalysis SymbolTable
-enter identifier info table
-    = maybe (identifierAlreadyDefinedError identifier) pure
-    $ SymbolTable.enter identifier info table
-
-identifierAlreadyDefinedError :: Identifier -> NameAnalysis a
-identifierAlreadyDefinedError = NameAnalysis
-    . lift
-    . throwE
-    . IdentifierAlreadyDefinedError
--}

lib/Language/Elna/Frontend/Parser.hs

@@ -93,10 +93,10 @@ expressionP :: Parser Expression
 expressionP = makeExprParser termP operatorTable
 
 variableAccessP :: Parser VariableAccess
-variableAccessP = VariableAccess <$> identifierP {- do
+variableAccessP = do
     identifier <- identifierP
     indices <- many $ bracketsP expressionP
-    pure $ foldr (flip ArrayAccess) (VariableAccess identifier) indices -}
+    pure $ foldr (flip ArrayAccess) (VariableAccess identifier) indices
 
 conditionP :: Parser Condition
 conditionP = do

lib/Language/Elna/Frontend/TypeAnalysis.hs

@@ -11,7 +11,7 @@ import Control.Monad.Trans.Reader (ReaderT, runReaderT, withReaderT, ask, asks)
 import Data.Foldable (traverse_)
 import qualified Data.Vector as Vector
 import qualified Language.Elna.Frontend.AST as AST
-import Language.Elna.Frontend.SymbolTable (Info(..), {-ParameterInfo(..), -}SymbolTable)
+import Language.Elna.Frontend.SymbolTable (Info(..), ParameterInfo(..), SymbolTable)
 import qualified Language.Elna.Frontend.SymbolTable as SymbolTable
 import Language.Elna.Frontend.Types (Type(..), booleanType, intType)
 import Language.Elna.Location (Identifier(..))
@@ -31,11 +31,10 @@ data Error
     | ArithmeticExpressionError Type
     | ComparisonExpressionError Type Type
     | InvalidConditionTypeError Type
-{-    | InvalidAssignmentError Type
-    | ExpectedLvalueError AST.Expression
-    | ArgumentTypeMismatchError Type Type
+    {- | ExpectedLvalueError AST.Expression
+    | ArgumentTypeMismatchError Type Type -}
     | ArrayIndexError Type
-    | ArrayAccessError Type -}
+    | ArrayAccessError Type
     deriving Eq
 
 instance Show Error
@@ -56,6 +55,10 @@ instance Show Error
         <> show lhs <> "\" and \"" <> show rhs <> "\""
     show (InvalidConditionTypeError got) =
         "Expected a condition to be a boolean, got: " <> show got
+    show (ArrayIndexError got) =
+        "Expected an array index expression to be an integer, got: " <> show got
+    show (ArrayAccessError got) =
+        "Expected to encounter an array, got: " <> show got
 
 newtype TypeAnalysis a = TypeAnalysis
     { runTypeAnalysis :: ReaderT SymbolTable (Except Error) a
@@ -127,7 +130,7 @@ statement globalTable = \case
             Nothing -> TypeAnalysis $ lift $ throwE
                 $ UndefinedSymbolError procedureName
   where
-    checkArgument SymbolTable.ParameterInfo{} _argument = pure () {-
+    checkArgument ParameterInfo{} _argument = pure () {-
         argumentType <- expression globalTable argument
         unless (argumentType == type')
             $ TypeAnalysis $ lift $ throwE $ ArgumentTypeMismatchError type' argumentType
@@ -145,7 +148,7 @@ variableAccess globalTable (AST.VariableAccess identifier) = do
             $ UnexpectedVariableInfoError anotherInfo
         Nothing -> TypeAnalysis $ lift $ throwE
             $ UndefinedSymbolError identifier
-{-variableAccess globalTable (AST.ArrayAccess arrayExpression indexExpression) = do
+variableAccess globalTable (AST.ArrayAccess arrayExpression indexExpression) = do
         arrayType <- variableAccess globalTable arrayExpression
         indexType <- expression globalTable indexExpression
         unless (indexType == intType)
@@ -154,7 +157,7 @@ variableAccess globalTable (AST.VariableAccess identifier) = do
             ArrayType _ baseType -> pure baseType
             nonArrayType -> TypeAnalysis $ lift $ throwE
                 $ ArrayAccessError nonArrayType
--}
+
 expression :: SymbolTable -> AST.Expression -> TypeAnalysis Type
 expression globalTable = \case
     AST.VariableExpression variableExpression ->