fixing expr->string issue

[rybern]

No description provided.

[SteveBronder]

Do you know how to fix the below so it matches on the sum type correctly? I'm getting errors that look like

This pattern matches values of type [? `Dim of 'a ]
but a pattern was expected which matches values of type
  [ `Dim of Middle__Expr.Typed.t
  | `SparseIterator of
      Middle__Expr.Typed.t * Middle__Expr.Typed.t * Middle__Expr.Typed.t ]
  sexp_list

let pp_validate_data ppf (name, st) =
  if String.is_suffix ~suffix:"__" name then ()
  else
  match SizedType.get_dims st with 
  | `Dim e ->
    pf ppf "@[<hov 4>context__.validate_dims(@,%S,@,%S,@,%S,@,%a);@]@ "
      "data initialization" name
      (stantype_prim_str (SizedType.to_unsized st))
      pp_call
      ("context__.to_vec", pp_expr, e)
  | `SparseIterator (nz_row, nz_col, nz_length) ->
    pf ppf "@[<hov 4>context__.validate_dims(@,%S,@,%S,@,%S,@,%a);@]@ "
    "data initialization" name
    (stantype_prim_str (SizedType.to_unsized st))
    pp_call
    ("context__.to_vec", pp_expr, nz_length)

odd because it looks similar to the thing we did with the for loop that does not flag an error

[rybern]

I think it's complaining that get_dims returns a list of that sum type, but you're only matching one.
If you wanted to do this for each dimension returned, you could use List.iter, like:

let pp_validate_data ppf (name, st) =
  if String.is_suffix ~suffix:"__" name then ()
  else
  List.iter (SizedType.get_dims st) ~f:(fun dim ->
    match dim with 
    | `Dim e -> ...
    | `SparseIterator .. -> ...
  )

[SteveBronder]

Excellent! Just to spot check my answer is street legal, I also put a [] around the item before the pp_expr else it complained that I wasn't giving it a sexp_list

let pp_validate_data ppf (name, st) =
  if String.is_suffix ~suffix:"__" name then ()
  else
  List.iter (SizedType.get_dims st) ~f:(fun dim ->
  match dim with
  | `Dim e  ->
    pf ppf "@[<hov 4>context__.validate_dims(@,%S,@,%S,@,%S,@,%a);@]@ "
      "data initialization" name
      (stantype_prim_str (SizedType.to_unsized st))
      pp_call
      ("context__.to_vec", pp_expr, [e])
  | `SparseIterator (_, _, nz_length)  ->
    pf ppf "@[<hov 4>context__.validate_dims(@,%S,@,%S,@,%S,@,%a);@]@ "
    "data initialization" name
    (stantype_prim_str (SizedType.to_unsized st))
    pp_call
    ("context__.to_vec", pp_expr, [nz_length])

[rybern]

I'm guessing pp_call is printing out a function call, so the third element there is the list of argument expressions? So adding the [] would be right if those are the only arguments to context__.to_vec