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|
type lambda =
Lambda of string * lambda
| Var of string
| Apply of lambda * lambda
(* We make the page more narrow for illustration purposes *)
let () = Format.set_margin 20
(* \n f x. n (\g h. h (g f)) (\u. x) (\u. u) *)
(* \n. \f. \x. n (\g. \h. h (g f)) (\u. x) (\u. u) *)
let sample_data =
Lambda (
"n",
(Lambda (
"f",
(Lambda (
"x",
Apply (
Apply (
Apply (
Var "n",
(Lambda (
"g",
(Lambda (
"h",
Apply (Var "h", Apply (Var "g", Var "f"))
)
)
)
)
),
(Lambda ("u", Var "x"))
),
(Lambda ("u", Var "u"))
)
)
)
)
)
)
(****************************************************************************)
(* Example from http://caml.inria.fr/resources/doc/guides/format.html
using Format directly. *)
open Format
let ident = pp_print_string;;
let kwd = pp_print_string;;
let rec pr_exp0 ppf = function
| Var s -> ident ppf s
| lam -> fprintf ppf "@[<1>(%a)@]" pr_lambda lam
and pr_app ppf = function
| e -> fprintf ppf "@[<2>%a@]" pr_other_applications e
and pr_other_applications ppf f =
match f with
| Apply (f, arg) -> fprintf ppf "%a@ %a" pr_app f pr_exp0 arg
| f -> pr_exp0 ppf f
and pr_lambda ppf = function
| Lambda (s, lam) ->
fprintf ppf "@[<1>%a%a%a@ %a@]" kwd "\\" ident s kwd "." pr_lambda lam
| e -> pr_app ppf e;;
let print_lambda x =
pr_lambda std_formatter x;
pp_print_flush std_formatter ()
let () =
print_endline
"Example from \
http://caml.inria.fr/resources/doc/guides/format.html#example";
print_lambda sample_data;
print_newline ()
(***************************************************************************)
(* Same example, using Easy_format *)
open Printf
open Easy_format
let p1 = { label with indent_after_label = 1 }
let p2 = { label with indent_after_label = 2 }
let paren_style =
{ list with
space_after_opening = false;
space_before_closing = false;
align_closing = false
}
let rec exp0_node = function
Var s -> Atom (s, atom)
| lam -> List (("(", "", ")", paren_style), [lambda_node lam])
and app_node = function
Apply (f, arg) -> Label ((app_node f, p2), exp0_node arg)
| f -> exp0_node f
and lambda_node = function
Lambda (s, lam) ->
Label ((Atom (sprintf "\\%s." s, atom), p1), lambda_node lam)
| e -> app_node e
let () =
print_endline "Same, using Easy_format:";
Pretty.to_stdout (lambda_node sample_data);
print_newline ()
|
