Generate the code for IfStatement

TODO

@@ -1 +1,4 @@
-# Register allocation
+# Intermediate code generation
+
+Execute the generation in a state monad and generate unique labels and
+temporary variable names.

lib/Language/Elna/Intermediate.hs

@@ -17,6 +17,7 @@ import qualified Language.Elna.AST as AST
 import Language.Elna.Types (Type(..))
 import Language.Elna.SymbolTable (SymbolTable, Info(..))
 import qualified Language.Elna.SymbolTable as SymbolTable
+import Data.Maybe (fromMaybe)
 
 data Operand
     = VariableOperand Variable
@@ -34,7 +35,7 @@ data Quadruple
     | GoToQuadruple Label
     | AssignQuadruple Operand Variable
     | ArrayQuadruple Variable Operand Variable
-    | ArrayAssignQuadruple Operand Word32 Variable
+    | ArrayAssignQuadruple Operand Operand Variable
     | AddQuadruple Operand Operand Variable
     | SubtractionQuadruple Operand Operand Variable
     | ProductQuadruple Operand Operand Variable
@@ -66,8 +67,58 @@ intermediate globalTable (AST.Program declarations) =
 
 statement :: SymbolTable -> AST.Statement -> Vector Quadruple
 statement _ AST.EmptyStatement = mempty
-statement globalTable (AST.CompoundStatement statements) =
+statement localTable (AST.AssignmentStatement variableAccess' assignee) =
-    foldMap (statement globalTable) statements
+    let (rhsOperand, rhsStatements) = expression localTable assignee
+        variableType' = variableType variableAccess' localTable
+        lhsStatements = case variableAccess localTable variableAccess' Nothing variableType' mempty of
+            (AST.Identifier identifier, Just accumulatedIndex, accumulatedStatements) ->
+                Vector.snoc accumulatedStatements
+                    $ ArrayAssignQuadruple rhsOperand accumulatedIndex
+                    $ Variable identifier
+            (AST.Identifier identifier, Nothing, accumulatedStatements) ->
+                Vector.snoc accumulatedStatements
+                    $ AssignQuadruple rhsOperand
+                    $ Variable identifier
+     in rhsStatements <> lhsStatements
+statement localTable (AST.IfStatement ifCondition ifStatement elseStatement) =
+    let (conditionStatements, jumpConstructor) = condition localTable ifCondition
+        ifStatements = statement localTable ifStatement
+        ifLabel = Label "L1"
+        endLabel = Label "L2"
+     in conditionStatements <> case statement localTable <$> elseStatement of
+        Just elseStatements -> Vector.cons (jumpConstructor ifLabel) elseStatements
+            <> Vector.fromList [GoToQuadruple endLabel, LabelQuadruple ifLabel]
+            <> Vector.snoc ifStatements (LabelQuadruple endLabel)
+        Nothing -> Vector.fromList [jumpConstructor ifLabel, GoToQuadruple endLabel, LabelQuadruple ifLabel]
+            <> Vector.snoc ifStatements (LabelQuadruple endLabel)
+statement localTable (AST.CompoundStatement statements) =
+    foldMap (statement localTable) statements
+
+condition :: SymbolTable -> AST.Condition -> (Vector Quadruple, Label -> Quadruple)
+condition localTable (AST.EqualCondition lhs rhs) =
+    let (lhsOperand, lhsStatements) = expression localTable lhs
+        (rhsOperand, rhsStatements) = expression localTable rhs
+     in (lhsStatements <> rhsStatements, EqualQuadruple lhsOperand rhsOperand)
+condition localTable (AST.NonEqualCondition lhs rhs) =
+    let (lhsOperand, lhsStatements) = expression localTable lhs
+        (rhsOperand, rhsStatements) = expression localTable rhs
+     in (lhsStatements <> rhsStatements, NonEqualQuadruple lhsOperand rhsOperand)
+condition localTable (AST.LessCondition lhs rhs) =
+    let (lhsOperand, lhsStatements) = expression localTable lhs
+        (rhsOperand, rhsStatements) = expression localTable rhs
+     in (lhsStatements <> rhsStatements, LessQuadruple lhsOperand rhsOperand)
+condition localTable (AST.GreaterCondition lhs rhs) =
+    let (lhsOperand, lhsStatements) = expression localTable lhs
+        (rhsOperand, rhsStatements) = expression localTable rhs
+     in (lhsStatements <> rhsStatements, GreaterQuadruple lhsOperand rhsOperand)
+condition localTable (AST.LessOrEqualCondition lhs rhs) =
+    let (lhsOperand, lhsStatements) = expression localTable lhs
+        (rhsOperand, rhsStatements) = expression localTable rhs
+     in (lhsStatements <> rhsStatements, LessOrEqualQuadruple lhsOperand rhsOperand)
+condition localTable (AST.GreaterOrEqualCondition lhs rhs) =
+    let (lhsOperand, lhsStatements) = expression localTable lhs
+        (rhsOperand, rhsStatements) = expression localTable rhs
+     in (lhsStatements <> rhsStatements, GreaterOrEqualQuadruple lhsOperand rhsOperand)
 
 variableAccess
     :: SymbolTable