Merge pull request #428 from c-cube/wip-pp

pretty printer
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Simon Cruanes 2023-06-01 15:03:05 -04:00 committed by GitHub
commit a8449e9847
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11 changed files with 793 additions and 3 deletions

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@ -1,4 +1,4 @@
version = 0.22.4 version = 0.24.1
profile=conventional profile=conventional
margin=80 margin=80
if-then-else=k-r if-then-else=k-r

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@ -30,7 +30,7 @@ update_next_tag:
sed -i "s/NEXT_VERSION/$(VERSION)/g" $(wildcard src/**/*.ml) $(wildcard src/**/*.mli) sed -i "s/NEXT_VERSION/$(VERSION)/g" $(wildcard src/**/*.ml) $(wildcard src/**/*.mli)
sed -i "s/NEXT_RELEASE/$(VERSION)/g" $(wildcard src/**/*.ml) $(wildcard src/**/*.mli) sed -i "s/NEXT_RELEASE/$(VERSION)/g" $(wildcard src/**/*.ml) $(wildcard src/**/*.mli)
WATCH?=@src/all @tests/runtest WATCH?=@src/check @tests/runtest
watch: watch:
@dune build $(WATCH) -w @dune build $(WATCH) -w

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src/pp/containers_pp.ml Normal file
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module B = Buffer
module Out = struct
type t = {
char: char -> unit;
(** Output a single char. The char is assumed not to be ['\n']. *)
sub_string: string -> int -> int -> unit;
(** Output a string slice (optim for [string]) *)
string: string -> unit; (** Output a string *)
newline: unit -> unit; (** Output a newline *)
}
let of_buffer (buf : Buffer.t) : t =
let char = B.add_char buf in
let sub_string = B.add_substring buf in
let string = B.add_string buf in
let newline () = B.add_char buf '\n' in
{ char; sub_string; string; newline }
let[@inline] char self c = self.char c
let[@inline] string self s = self.string s
let[@inline] sub_string self s i len = self.sub_string s i len
let[@inline] newline self = self.newline ()
end
module Ext = struct
type 'a t = {
pre: Out.t -> 'a -> unit; (** Printed before the wrapped value. *)
post: Out.t -> 'a -> unit; (** Printed after the wrapped value. *)
}
end
type t = {
view: view; (** Document view *)
wfl: int; (** Width if flattened *)
}
and view =
| Nil
| Newline
| Nest of int * t
| Append of t * t
| Char of char
| Text of string
| Text_sub of string * int * int
| Text_zero_width of string
| Group of t
| Fill of { sep: t; l: t list }
| Wrap : 'a Ext.t * 'a * t -> view
(* debug printer *)
let rec debug out (self : t) : unit =
match self.view with
| Nil -> Format.fprintf out "nil"
| Newline -> Format.fprintf out "nl"
| Nest (i, x) -> Format.fprintf out "(@[nest %d@ %a@])" i debug x
| Append (a, b) -> Format.fprintf out "@[%a ^@ %a@]" debug a debug b
| Char c -> Format.fprintf out "%C" c
| Text s -> Format.fprintf out "%S" s
| Text_zero_width s -> Format.fprintf out "(zw %S)" s
| Text_sub (s, i, len) -> Format.fprintf out "%S" (String.sub s i len)
| Group d -> Format.fprintf out "(@[group@ %a@])" debug d
| Fill { sep = _; l } ->
Format.fprintf out "(@[fill@ %a@])" (Format.pp_print_list debug) l
| Wrap (_, _, d) -> Format.fprintf out "(@[ext@ %a@])" debug d
let nil : t = { view = Nil; wfl = 0 }
let newline : t = { view = Newline; wfl = 1 }
let nl = newline
let char c =
if c = '\n' then
nl
else
{ view = Char c; wfl = 1 }
let nest i x : t =
match x.view with
| _ when i <= 0 -> x
| Nil -> nil
| _ -> { view = Nest (i, x); wfl = x.wfl }
let append a b : t =
match a.view, b.view with
| Nil, _ -> b
| _, Nil -> a
| _ -> { view = Append (a, b); wfl = a.wfl + b.wfl }
let group d : t =
match d.view with
| Nil -> nil
| Group _ -> d
| _ -> { view = Group d; wfl = d.wfl }
let ext ext v d : t = { view = Wrap (ext, v, d); wfl = d.wfl }
let ( ^ ) = append
let text_sub_ s i len : t = { view = Text_sub (s, i, len); wfl = len }
(* Turn [str], which contains some newlines, into a document.
We make a concatenation of
each line's content followed by a newline.
Then we group the result so that it remains in a unified block. *)
let split_text_ (str : string) : t =
let cur = ref nil in
let i = ref 0 in
let len = String.length str in
while !i < len do
match String.index_from str !i '\n' with
| exception Not_found ->
(* last chunk *)
if !i + 1 < len then cur := !cur ^ text_sub_ str !i (len - !i);
i := len
| j ->
cur := !cur ^ text_sub_ str !i (j - !i) ^ nl;
i := j + 1
done;
!cur
let text (str : string) : t =
if str = "" then
nil
else if String.contains str '\n' then
split_text_ str
else
{ view = Text str; wfl = String.length str }
let textpf fmt = Printf.ksprintf text fmt
let textf fmt = Format.kasprintf text fmt
module Flatten = struct
let to_out (out : Out.t) (self : t) : unit =
let rec loop (d : t) =
match d.view with
| Nil -> ()
| Char c -> out.char c
| Newline -> out.char ' '
| Nest (_, x) -> loop x
| Append (x, y) ->
loop x;
loop y
| Text s | Text_zero_width s -> out.string s
| Text_sub (s, i, len) -> out.sub_string s i len
| Group x -> loop x
| Fill { sep; l } ->
List.iteri
(fun i x ->
if i > 0 then loop sep;
loop x)
l
| Wrap (ext, v, d) ->
ext.pre out v;
loop d;
ext.post out v
in
loop self
let to_buffer buf (self : t) : unit =
let out = Out.of_buffer buf in
to_out out self
let to_string self : string =
let buf = Buffer.create 32 in
to_buffer buf self;
Buffer.contents buf
end
module Pretty = struct
type st = { out: Out.t; width: int }
(** Add [i] spaces of indentation. *)
let add_indent st (i : int) =
for _i = 1 to i do
st.out.char ' '
done
let rec pp_flatten (st : st) (self : t) : int =
match self.view with
| Nil -> 0
| Char c ->
st.out.char c;
1
| Newline ->
st.out.char ' ';
1
| Nest (_i, x) -> pp_flatten st x
| Append (x, y) ->
let n = pp_flatten st x in
n + pp_flatten st y
| Text s ->
st.out.string s;
String.length s
| Text_zero_width s ->
st.out.string s;
0
| Text_sub (s, i, len) ->
st.out.sub_string s i len;
len
| Group x -> pp_flatten st x
| Fill { sep; l } ->
(* print separated by spaces *)
let n = ref 0 in
List.iteri
(fun i x ->
if i > 0 then n := !n + pp_flatten st sep;
n := !n + pp_flatten st x)
l;
!n
| Wrap (ext, v, d) ->
ext.pre st.out v;
let n = pp_flatten st d in
ext.post st.out v;
n
(** Does [x] fit in the current line when flattened, given that [k] chars
are already on the line? *)
let[@inline] fits_flattened st k x = x.wfl <= st.width - k
let pp_newline (st : st) i =
st.out.char '\n';
add_indent st i
(** Print [self] into the buffer.
@param k how many chars are already printed on the current line
*)
let rec pp_rec (st : st) (k : int) (stack : (int * t) list) : unit =
match stack with
| [] -> ()
| (i, d) :: stack_tl ->
pp_rec_top st ~k ~i d (fun k -> pp_rec st k stack_tl)
(** Print [d] at indentation [i], with [k] chars already printed
on the current line, then calls [kont] with the
new [k]. *)
and pp_rec_top st ~k ~i d (kont : int -> unit) : unit =
match d.view with
| Nil -> kont k
| Char c ->
st.out.char c;
kont (k + 1)
| Newline ->
pp_newline st i;
kont i
| Nest (j, x) -> pp_rec_top st ~k ~i:(i + j) x kont
| Append (x, y) ->
(* print [x], then print [y] *)
pp_rec_top st ~k ~i x (fun k -> pp_rec_top st ~k ~i y kont)
| Text s ->
st.out.string s;
kont (k + String.length s)
| Text_zero_width s ->
st.out.string s;
kont k
| Text_sub (s, i, len) ->
st.out.sub_string s i len;
kont (k + len)
| Group x ->
if fits_flattened st k x then (
(* print flattened *)
let w_x = pp_flatten st x in
assert (w_x = x.wfl);
kont (k + w_x)
) else
pp_rec_top st ~k ~i x kont
| Fill { sep; l } -> pp_fill st ~k ~i sep l kont
| Wrap (ext, v, d) ->
ext.pre st.out v;
pp_rec_top st ~k ~i d (fun k ->
ext.post st.out v;
kont k)
and pp_fill st ~k ~i sep l (kont : int -> unit) : unit =
(* [k] is the current offset in the line *)
let rec loop idx k l =
match l with
| x :: tl ->
if fits_flattened st k x then (
(* all flattened *)
let w_sep =
if idx = 0 then
0
else
pp_flatten st sep
in
let w_x = pp_flatten st x in
assert (w_x = x.wfl);
loop (idx + 1) (k + w_x + w_sep) tl
) else (
(* print, followed by a newline and resume filling with [k=i] *)
let pp_and_continue k =
pp_rec_top st ~k ~i x (fun k -> loop (idx + 1) k tl)
in
if idx > 0 then
(* separator, then item *)
pp_rec_top st ~k ~i sep pp_and_continue
else
pp_and_continue k
)
| [] -> kont k
in
loop 0 k l
let to_out ~width out (self : t) : unit =
let st = { out; width } in
pp_rec st 0 [ 0, self ]
let to_buffer ~width (buf : Buffer.t) (self : t) : unit =
to_out ~width (Out.of_buffer buf) self
let to_string ~width (self : t) : string =
let buf = Buffer.create 32 in
to_buffer ~width buf self;
Buffer.contents buf
let to_format ~width out self : unit =
(* TODO: more efficient implementation based on out *)
CCFormat.string_lines out (to_string ~width self)
end
let pp = Pretty.to_format ~width:80
(* helpers *)
let sp = char ' '
module Infix = struct
let ( ^ ) = append
let[@inline] ( ^+ ) x y = x ^ sp ^ y
let[@inline] ( ^/ ) x y = x ^ nl ^ y
end
include Infix
let true_ = text "true"
let false_ = text "false"
let bool b =
if b then
true_
else
false_
let int x : t = text (string_of_int x)
let float x : t = text (string_of_float x)
let float_hex x : t = textpf "%h" x
let text_quoted s : t = text (Printf.sprintf "%S" s)
let text_zero_width s : t = { view = Text_zero_width s; wfl = 0 }
let append_l ?(sep = nil) l =
let rec loop = function
| [] -> nil
| [ x ] -> x
| x :: tl -> x ^ sep ^ loop tl
in
loop l
let append_sp l = append_l ~sep:sp l
let append_nl l = append_l ~sep:nl l
let fill sep = function
| [] -> nil
| [ x ] -> x
| l ->
(* flattened: just like concat *)
let wfl =
List.fold_left (fun wfl x -> wfl + x.wfl) 0 l
+ ((List.length l - 1) * sep.wfl)
in
{ view = Fill { sep; l }; wfl }
let fill_map sep f l = fill sep (List.map f l)
let of_list ?(sep = nil) f l =
let rec loop = function
| [] -> nil
| [ x ] -> f x
| x :: tl -> f x ^ sep ^ loop tl
in
loop l
let of_seq ?(sep = nil) f seq : t =
let rec loop first seq =
match seq () with
| Seq.Nil -> nil
| Seq.Cons (x, tl) ->
let x = f x in
(if first then
x
else
sep ^ x)
^ loop false tl
in
loop true seq
let bracket l d r : t = group (text l ^ nest (String.length l) d ^ text r)
let bracket2 l d r : t = group (text l ^ nest 2 (nl ^ d) ^ nl ^ text r)
let sexp_l l : t = char '(' ^ nest 1 (group (append_nl l ^ char ')'))
let sexp_apply a l : t = sexp_l (text a :: l)
module Dump = struct
let list l : t =
let sep = char ';' ^ nl in
group (char '[' ^ nest 1 (fill sep l) ^ char ']')
end
module Term_color = struct
type color =
[ `Black | `Red | `Yellow | `Green | `Blue | `Magenta | `Cyan | `White ]
type style =
[ `FG of color (* foreground *)
| `BG of color (* background *)
| `Bold
| `Reset
| `Underline ]
let int_of_color_ = function
| `Black -> 0
| `Red -> 1
| `Green -> 2
| `Yellow -> 3
| `Blue -> 4
| `Magenta -> 5
| `Cyan -> 6
| `White -> 7
let code_of_style : style -> int = function
| `FG c -> 30 + int_of_color_ c
| `BG c -> 40 + int_of_color_ c
| `Bold -> 1
| `Reset -> 0
| `Underline -> 4
let spf = Printf.sprintf
let string_of_style a = spf "\x1b[%dm" (code_of_style a)
let reset = string_of_style `Reset
let string_of_style_list = function
| [] -> reset
| [ a ] -> string_of_style a
| [ a; b ] -> spf "\x1b[%d;%dm" (code_of_style a) (code_of_style b)
| [ a; b; c ] ->
spf "\x1b[%d;%d;%dm" (code_of_style a) (code_of_style b) (code_of_style c)
| l ->
let buf = Buffer.create 32 in
let pp_num c = Buffer.add_string buf (string_of_int (code_of_style c)) in
Buffer.add_string buf "\x1b[";
List.iteri
(fun i c ->
if i > 0 then Buffer.add_char buf ';';
pp_num c)
l;
Buffer.add_string buf "m";
Buffer.contents buf
(* TODO: handle nested styles *)
let ext_style_ : style list Ext.t =
{
pre = (fun out l -> Out.string out (string_of_style_list l));
post = (fun out _l -> Out.string out reset);
}
(** Set the foreground color. *)
let color (c : color) (d : t) : t = ext ext_style_ [ `FG c ] d
(** Set a full style for this document. *)
let style_l (l : style list) (d : t) : t = ext ext_style_ l d
end

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(** Pretty printing of documents.
A document is a structured tree of text with
formatting instructions.
It can be rendered into a string ("pretty printed"),
see {!Pretty}.
This follows Wadler's paper "A prettier printer", but with
some changes in the rendering part because we can't rely on lazyness
to make the algebraic implementation efficient.
Some general considerations: the type [t] is the type of documents,
a tree with text leaves that is pretty printed within a given width.
Layout is controlled via the combination of a few primitives:
- [newline] will either print a space or a newline. It is similar
to {!Format}'s ["@ "] in that sense. A big difference with [Format]
is that by default [newline] is actually a newline. It only
becomes a space if it's in a [group] small enough to fit
in the remainder of the current line.
- [group d] tries to write [d] on a single line if there's room.
If not, it has no effect.
- [nest n d] increases the indentation level inside [d]. Any newline
that is rendered as a new line is indented by [n] more spaces (which
are cumulative with surrounding [nest] calls).
- [append a b] (or [a ^ b]) just prints [a] followed by [b].
- [fill d] is a bit like [group] but it will try to cram
as much as possible on each line. It is not all-or-nothing
like [group].
*)
(** {2 Core} *)
type t
(** The type of documents *)
val nil : t
(** Empty document *)
val char : char -> t
(** Single char. *)
val text : string -> t
(** Text. The string will be split on ['\n'], which are replaced
by {!newline}. *)
val textpf : ('a, unit, string, t) format4 -> 'a
(** Text, with a {!Printf}-compatible format.
For example, [textpf "%d-%d" 4 2] is like [text "4-2"]. *)
val textf : ('a, Format.formatter, unit, t) format4 -> 'a
(** Text, with a {!Format}-compatible format.
Note that this will bake-in any formatting done by {!Format}.
Newlines introduced by format will become hard newlines
in the resulting document. *)
val nest : int -> t -> t
(** [nest n d] increases indentation by [n] inside [d].
If current indentation is [m], then every newline inside [d]
will be followed by [n + m] leading spaces. *)
val group : t -> t
(** Group the documents inside this.
Newlines immediately inside this group will either
render as new lines or as spaces, depending on the width available. *)
val append : t -> t -> t
(** Concatenation. *)
val newline : t
(** A line break. *)
val nl : t
(** Alias for {!newline} *)
val fill : t -> t list -> t
(** [fill sep l] resembles [group (append_l ~sep l)], except it tries
to put as many items of [l] as possible on each line.
In terms of {!Format}, this is like the hov box. *)
(** {2 Output device} *)
(** Arbitrary output.
This is used for user-provided output. *)
module Out : sig
type t = {
char: char -> unit;
(** Output a single char. The char is assumed not to be ['\n']. *)
sub_string: string -> int -> int -> unit;
(** Output a string slice (optim for [string]) *)
string: string -> unit; (** Output a string *)
newline: unit -> unit; (** Output a newline *)
}
val of_buffer : Buffer.t -> t
val char : t -> char -> unit
val string : t -> string -> unit
val sub_string : t -> string -> int -> int -> unit
val newline : t -> unit
end
(** {2 Extensibility} *)
(** Extension node.
Custom nodes can be used to add user-defined behavior to
the rendered output. For example, documents
might be annotated with ANSI-terminal colors, or
with HTML tags. *)
module Ext : sig
type 'a t = {
pre: Out.t -> 'a -> unit; (** Printed before the wrapped value. *)
post: Out.t -> 'a -> unit; (** Printed after the wrapped value. *)
}
(** An extension is a custom document node. It takes a value of type ['a],
and a document [d], and can output what it wants based
on the custom value before and after [d] is printed.
The extension is considered to have width [0]. *)
end
val ext : 'a Ext.t -> 'a -> t -> t
(** [ext e v d] wraps [d] with value [v].
It is a document that has the same
shape (and size) as [d], except that additional data will
be output when it is rendered using extension [e].
When this is rendered, first [e.pre out v] is called;
then [d] is printed; then [e.post out v] is called.
Here [out] is the output buffer/stream for rendering.
*)
(** {2 Pretty print and rendering} *)
(** Pretty-printing.
These functions are parametrized by a width,
and will try to fit the result within this width. *)
module Pretty : sig
val to_out : width:int -> Out.t -> t -> unit
(** Render to an arbitrary output. *)
val to_string : width:int -> t -> string
(** Render to a string. *)
val to_buffer : width:int -> Buffer.t -> t -> unit
(** Render to a buffer. *)
val to_format : width:int -> Format.formatter -> t -> unit
end
(** Trivial printing, on a single line.
This is generally ugly, but it's simple and fast when we do not
care about looks. *)
module Flatten : sig
val to_out : Out.t -> t -> unit
val to_buffer : Buffer.t -> t -> unit
val to_string : t -> string
end
val pp : Format.formatter -> t -> unit
(** Pretty-print, using {!Pretty} and an unspecified margin. *)
val debug : Format.formatter -> t -> unit
(** Debug printer. This prints the structure of the document,
it does {b not} pretty-print it. See {!pp} or {!Pretty}. *)
(** {2 Convenience functions} *)
module Infix : sig
val ( ^ ) : t -> t -> t
(** Alias of {!append}. *)
val ( ^+ ) : t -> t -> t
(** [x ^+ y] is [x ^ text " " ^ y] *)
val ( ^/ ) : t -> t -> t
(** [x ^/ y] is [x ^ newline ^ y] *)
end
include module type of Infix
val sp : t
(** A single space *)
val append_l : ?sep:t -> t list -> t
(** [append_l ?sep l] is the concatenation of elements of
[l], separated by [sep] (default [nil]) *)
val append_sp : t list -> t
(** [append_sp l] is the concatenation of elements of [l], separated by [' '] *)
val append_nl : t list -> t
(** Same as {!append_l} with [sep=nl] *)
val fill_map : t -> ('a -> t) -> 'a list -> t
(** [fill_map sep f l] is [fill sep (List.map f l)] *)
val bool : bool -> t
val int : int -> t
val float : float -> t
val float_hex : float -> t
val text_quoted : string -> t
(** [text_quoted s] is [text (spf "%S" s)] *)
val text_zero_width : string -> t
(** Text but we assume it takes no space on screen. *)
val of_list : ?sep:t -> ('a -> t) -> 'a list -> t
(** [of_list f l] maps each element of [l] to a document
and concatenates them.
@param sep separator inserted between elements (default [nil]) *)
val of_seq : ?sep:t -> ('a -> t) -> 'a Seq.t -> t
(** Same as {!of_list} but with sequences. *)
val bracket : string -> t -> string -> t
(** [bracket l d r] groups [d], between brackets [l] and [r] *)
val bracket2 : string -> t -> string -> t
(** [bracket2 l d r] groups [d], indented by 2, between brackets [l] and [r] *)
val sexp_apply : string -> t list -> t
(** [sexp_apply a l] is the S-expr ["(text a …l)"], pretty-printed *)
val sexp_l : t list -> t
(** [sexp_l [l1;…ln]] is the S-expr ["(l1 l2…ln)"], pretty-printed *)
(** Printers that correspond closely to OCaml's syntax. *)
module Dump : sig
val list : t list -> t
end
(** Simple colors in terminals *)
module Term_color : sig
type color =
[ `Black | `Blue | `Cyan | `Green | `Magenta | `Red | `White | `Yellow ]
type style = [ `BG of color | `Bold | `FG of color | `Reset | `Underline ]
val color : color -> t -> t
val style_l : style list -> t -> t
end

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(library
(name containers_pp)
(public_name containers.pp)
(synopsis "Pretty printer for Containers")
(flags :standard)
(libraries containers seq))

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@ -6,5 +6,6 @@
(preprocess (preprocess
(action (action
(run %{project_root}/src/core/cpp/cpp.exe %{input-file}))) (run %{project_root}/src/core/cpp/cpp.exe %{input-file})))
(libraries containers containers.bencode containers.cbor containers.unix (libraries containers containers.bencode containers.cbor
containers.unix containers.pp
threads containers_testlib iter gen uutf csexp)) threads containers_testlib iter gen uutf csexp))

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@ -1,5 +1,6 @@
Containers_testlib.run_all ~descr:"containers" Containers_testlib.run_all ~descr:"containers"
[ [
T_pp.get ();
T_list.get (); T_list.get ();
T_array.get (); T_array.get ();
T_bool.get (); T_bool.get ();

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include (val Containers_testlib.make ~__FILE__ ())
open Containers_pp
let spf = Printf.sprintf
let () =
eq "hello world" (Flatten.to_string @@ text "hello" ^ newline ^ text "world")
let () =
eq ~name:"split text" ~printer:(spf "%S") "let rec f x =\n x+2\n"
(let d = text "let rec f x =\n x+2\n" in
Pretty.to_string ~width:15 d)
let () =
eq ~name:"l1" ~printer:(spf "%S") "[0; 1; 2; 3;\n 4; 5; 6; 7;\n 8; 9]"
(let d = Dump.list (CCList.init 10 int) in
Pretty.to_string ~width:10 d)
let () =
eq ~name:"l2" ~printer:(spf "%S")
"[[0; 1; 2; 3;\n\
\ 4; 5];\n\
\ [1; 2; 3; 4;\n\
\ 5; 6];\n\
\ [2; 3; 4; 5;\n\
\ 6; 7];\n\
\ [3; 4; 5; 6;\n\
\ 7; 8];\n\
\ [4; 5; 6; 7;\n\
\ 8; 9];\n\
\ [5; 6; 7; 8;\n\
\ 9; 10]]"
(let d =
Dump.list
(CCList.init 6 (fun i ->
Dump.list (CCList.init 6 (fun j -> int @@ (i + j)))))
in
Pretty.to_string ~width:10 d)
let () =
eq ~name:"s1" ~printer:(spf "%S") "(foo\n bar\n baaz\n (g 42 10))"
(let d =
sexp_apply "foo"
[ text "bar"; text "baaz"; sexp_apply "g" [ int 42; int 10 ] ]
in
Pretty.to_string ~width:10 d)
let ext_coucou =
{
Ext.pre = (fun out () -> out.string "<coucou>");
post = (fun out () -> out.string "</coucou>");
}
let () =
eq ~name:"wrap1" ~printer:(spf "%S")
"(foo\n bar\n <coucou>(g 42 10)</coucou>)"
(let d =
sexp_apply "foo"
[ text "bar"; ext ext_coucou () (sexp_apply "g" [ int 42; int 10 ]) ]
in
Pretty.to_string ~width:10 d)