(* Abstract syntax for uSQL, very simple SQL SELECT statements 
   sestoft@dina.kvl.dk 2001-02-22
 *)

datatype constant =
    CstI of int                         (* Integer constant               *)
  | CstB of bool                        (* Boolean constant               *)
  | CstS of string                      (* String constant                *)

datatype stmt =
    Select of expr list                 (* fields are expressions         *)
            * string list               (* FROM ...                       *)

and column =
    Column of string                    (* A column name: c               *)
  | TableColumn of string * string      (* A qualified column: t.c        *)

and expr = 
    Star
  | Cst of constant                     (* Constant                       *)
  | ColumnExpr of column                (* Column                         *)
  | Prim of string * expr list          (* Builtin function               *)