add types in LogicIR

src/LogicIR/Expr.hs

@@ -2,6 +2,18 @@ module LogicIR.Expr where
 
 -- Based on my (Duncan's) previous work: https://github.com/mrexodia/wp/blob/master/Wp.hs
 
+data Primitive = PBool
+               | PInt
+               deriving (Show, Eq, Read)
+
+data Type = TPrim Primitive
+          | TArray Type
+          deriving (Show, Eq, Read)
+
+-- Typed + named variable
+data Var = Var Type String
+         deriving (Show, Eq, Read)
+
 -- Numeral unary operators
 data NUnop = NNeg
            | NNot
@@ -22,10 +34,10 @@ data NBinop = NAdd
 
 -- Numeral expressions
 data NExpr = NConst Int -- Integer constant
-           | NVar String -- Named integer variable
+           | NVar Var -- Variable
            | NUnop NUnop NExpr -- Unary operator
            | NBinop NExpr NBinop NExpr -- Binary operators
-           | NArray String NExpr -- Integer array access
+           | NArray Var NExpr -- Integer array access
            deriving (Show, Eq, Read)
 
 -- Reference: https://en.wikipedia.org/wiki/First-order_logic#Logical_symbols
@@ -51,10 +63,10 @@ data COp = CEqual
 
 -- Logical expressions
 data LExpr = LConst Bool -- True/False
-           | LVar String -- Named boolean variable
+           | LVar Var -- Variable
            | LNot LExpr -- Logical negation/not
            | LBinop LExpr LBinop LExpr -- Logical operator
            | LComp NExpr COp NExpr -- Integer comparison
-           | LQuant QOp [String] LExpr -- Logical quantifier
-           | LArray String NExpr -- Logical array access (TODO: remove?)
+           | LQuant QOp [Var] LExpr -- Logical quantifier
+           | LArray Var NExpr -- Logical array access (TODO: remove?)
            deriving (Show, Eq, Read)
\ No newline at end of file

src/LogicIR/Fold.hs

@@ -4,10 +4,10 @@ import LogicIR.Expr
 
 -- Fold algrbra for numeral expressions
 type NExprAlgebra r = (Int -> r, -- NConst
-                       String -> r, -- NVar
+                       Var -> r, -- NVar
                        NUnop -> r -> r, -- NUnop
                        r -> NBinop -> r -> r, -- NBinop
-                       String -> r -> r -- NArray
+                       Var -> r -> r -- NArray
                       )
 
 -- Fold for numeral expressions
@@ -22,12 +22,12 @@ foldNExpr (fConst, fVar, fUnop, fBinop, fArray) = fold where
 
 -- Fold algebra for logical expressions
 type LExprAlgebra r = (Bool -> r, -- LConst
-                       String -> r, -- LVar
+                       Var -> r, -- LVar
                        r -> r, -- LNot
                        r -> LBinop -> r -> r, -- LBinop
                        NExpr -> COp -> NExpr -> r, -- LComp
-                       QOp -> [String] -> r -> r, -- LQuant
-                       String -> NExpr -> r -- LArray
+                       QOp -> [Var] -> r -> r, -- LQuant
+                       Var -> NExpr -> r -- LArray
                       )
 
 -- Fold for logical expressions