ppStatement (WhileStmt expr stmt)
  = (text "while" <+> parens (ppExpr expr)) `nestStmt` ppStatement stmt
ppStatement (WhileStmt expr stmt)
  = (text "while" <+> parens (ppExpr expr)) `nestStmt` ppStatement stmt
ppStatement (WhileStmt expr stmt)
  = (text "while" <+> parens (ppExpr expr)) `nestStmt` ppStatement stmt