1 files changed, 45 insertions, 0 deletions
diff --git a/paper/While/WhileCommon.dcl b/paper/While/WhileCommon.dcl
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--- /dev/null
+++ b/paper/While/WhileCommon.dcl
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+definition module WhileCommon
+
+from StdOverloaded import class toString, class zero
+from GenEq import generic gEq
+from Common import ::Either, ::Error
+from WhileLexer import ::Token
+from Yard import ::Parser
+
+:: Var :== String
+
+:: State :== Var -> Either Error Int
+
+:: AExpr = Var Var
+         | Lit Int
+         | Op AExpr Operator AExpr
+
+:: Operator = Add | Sub | Mul | Div
+
+:: BExpr = Bool Bool
+         | Not BExpr
+         | And BExpr BExpr
+         | Or BExpr BExpr
+         | Comp AExpr Comparator AExpr
+
+:: Comparator = Eq | Ne | Le | Lt | Ge | Gt
+
+derive gEq AExpr, Operator, BExpr, Comparator
+
+instance zero State
+
+instance toString AExpr
+instance toString Operator
+instance toString BExpr
+instance toString Comparator
+
+class run s :: s State -> Either Error State
+
+class eval i o :: i State -> Either Error o
+instance eval AExpr Int
+instance eval BExpr Bool
+
+class parse o :: [Token] -> Either Error o
+
+paexpr :: Parser Token AExpr
+pbexpr :: Parser Token BExpr