Access multidimensional arrays

1 files changed, 31 insertions, 18 deletions

diff --git a/lib/Language/Elna/Parser.hs b/lib/Language/Elna/Parser.hs
index cee533e..aa7c315 100644
--- a/lib/Language/Elna/Parser.hs
+++ b/lib/Language/Elna/Parser.hs
@@ -9,7 +9,9 @@ import Data.Text (Text)
 import qualified Data.Text as Text
 import Data.Void (Void)
 import Language.Elna.AST
-    ( Declaration(..)
+    ( VariableAccess(..)
+    , Condition(..)
+    , Declaration(..)
     , Expression(..)
     , Identifier(..)
     , Literal(..)
@@ -21,12 +23,12 @@ import Language.Elna.AST
     )
 import Text.Megaparsec
     ( Parsec
+    , MonadParsec(..)
     , (<?>)
     , optional
     , between
     , sepBy
     , choice
-    , MonadParsec(..)
     )
 import Text.Megaparsec.Char
     ( alphaNumChar
@@ -124,19 +126,23 @@ termP :: Parser Expression
 termP = choice
     [ parensP expressionP
     , LiteralExpression <$> literalP
-    , VariableExpression <$> identifierP
+    , VariableExpression <$> variableAccessP
     ]
 
+variableAccessP :: Parser VariableAccess
+variableAccessP = do
+    identifier <- identifierP
+    indices <- many $ bracketsP expressionP
+    pure $ foldr (flip ArrayAccess) (VariableAccess identifier) indices
+
 operatorTable :: [[Operator Parser Expression]]
 operatorTable =
-    [ [Postfix (flip ArrayExpression <$> bracketsP expressionP)]
-    , unaryOperator
+    [ unaryOperator
     , factorOperator
     , termOperator
-    , comparisonOperator
     ]
   where
-    unaryOperator = 
+    unaryOperator =
         [ prefix "-" NegationExpression
         , prefix "+" id
         ]
@@ -148,20 +154,27 @@ operatorTable =
         [ binary "+" SumExpression
         , binary "-" SubtractionExpression
         ]
-    comparisonOperator =
-        [ binary "<" LessExpression
-        , binary "<=" LessOrEqualExpression
-        , binary ">" GreaterExpression
-        , binary ">=" GreaterOrEqualExpression
-        , binary "=" EqualExpression
-        , binary "#" NonEqualExpression
-        ]
     prefix name f = Prefix (f <$ symbol name)
     binary name f = InfixL (f <$ symbol name)
 
 expressionP :: Parser Expression
 expressionP = makeExprParser termP operatorTable
 
+conditionP :: Parser Condition
+conditionP = do
+    lhs <- expressionP
+    conditionCons <- choice comparisonOperator
+    conditionCons lhs <$> expressionP
+  where
+    comparisonOperator =
+        [ symbol "<" >> pure LessCondition
+        , symbol "<=" >> pure LessOrEqualCondition
+        , symbol ">" >> pure GreaterCondition
+        , symbol ">=" >> pure GreaterOrEqualCondition
+        , symbol "=" >> pure EqualCondition
+        , symbol "#" >> pure NonEqualCondition
+        ]
+
 statementP :: Parser Statement
 statementP
     = EmptyStatement <$ semicolonP
@@ -173,18 +186,18 @@ statementP
     <?> "statement"
   where
     ifElseP = IfStatement
-        <$> (symbol "if" *> parensP expressionP)
+        <$> (symbol "if" *> parensP conditionP)
         <*> statementP
         <*> optional (symbol "else" *> statementP)
     whileP = WhileStatement
-        <$> (symbol "while" *> parensP expressionP)
+        <$> (symbol "while" *> parensP conditionP)
         <*> statementP
     callP = CallStatement
         <$> identifierP
         <*> parensP (sepBy expressionP commaP)
         <* semicolonP
     assignmentP = AssignmentStatement
-        <$> expressionP
+        <$> variableAccessP
         <* symbol ":="
         <*> expressionP
         <* semicolonP