sig
  val compile_statement :
    Logical_algebra_types.logical_compile_context ->
    Xquery_core_ast.acstatement -> Logical_algebra_types.logical_algop_expr
  val compile_prolog :
    Logical_algebra_types.logical_compile_context ->
    Xquery_core_ast.acprolog ->
    Logical_algebra_types.logical_compile_context *
    Logical_algebra_types.logical_algop_prolog
  val compile_xmodule :
    Logical_algebra_types.logical_compile_context ->
    Xquery_core_ast.acxmodule ->
    Logical_algebra_types.logical_compile_context *
    Logical_algebra_types.logical_algop_xmodule
end