Shells in OCaml
Built-in: read
Initial support for the `read` built-in, no <backslash> escape handling
(TODO).
+100
+28
src/lib/built_ins.ml
+28
src/lib/built_ins.ml
···
94
94
| Return of int
95
95
| Umask of int option
96
96
| Shift of int option
97
+
| Read of bool * string list
97
98
98
99
let reserved = [ "fg"; "bg"; "jobs" ]
99
100
let pp_args = Fmt.(list ~sep:(Fmt.any " ") string)
···
126
127
| Ignore -> "ignore"
127
128
| Default -> "default")
128
129
| Set _ -> "set"
130
+
| Read (backslash, vars) ->
131
+
Fmt.str "read%s %a" (if backslash then " -r" else " ") pp_args vars
129
132
130
133
(* Change Directory *)
131
134
module Cd = struct
···
495
498
Cmd.v info term
496
499
end
497
500
501
+
module Read = struct
502
+
open Cmdliner
503
+
504
+
let r =
505
+
let doc =
506
+
"Do not treat <backslash> character in any special way. Consider each \
507
+
<backslash> to be part of the input line."
508
+
in
509
+
Arg.(value & flag & info [ "r" ] ~doc)
510
+
511
+
let args =
512
+
let doc = "Names of existing or non-existing shell variables." in
513
+
Arg.(value & pos_all string [] & info [] ~docv:"var" ~doc)
514
+
515
+
let t =
516
+
let make_read r args = Read (r, args) in
517
+
let term = Term.(const make_read $ r $ args) in
518
+
let info =
519
+
let doc = "Read from standard input into shell variables." in
520
+
Cmd.info "read" ~doc
521
+
in
522
+
Cmd.v info term
523
+
end
524
+
498
525
let of_args (w : string list) =
499
526
let open Cmdliner in
500
527
let exec_cmd cmd v =
···
524
551
| "return" :: _ as cmd -> exec_cmd cmd Return.t
525
552
| "umask" :: _ as cmd -> exec_cmd cmd Umask.t
526
553
| "shift" :: _ as cmd -> exec_cmd cmd Shift.t
554
+
| "read" :: _ as cmd -> exec_cmd cmd Read.t
527
555
| cmd :: _ ->
528
556
if List.mem cmd reserved then begin
529
557
Debug.Log.err (fun f -> f "Unimplemented built-in: %s" cmd);
+1
src/lib/built_ins.mli
+1
src/lib/built_ins.mli
+36
src/lib/eval.ml
+36
src/lib/eval.ml
···
1365
1365
assert (new_len >= 0);
1366
1366
let argv = Array.init new_len (fun i -> Array.get ctx.argv (i + n)) in
1367
1367
Exit.zero { ctx with argv }
1368
+
| Read (_backslash, vars) -> (
1369
+
let line =
1370
+
let buf = Cstruct.create 1 in
1371
+
let rec loop acc =
1372
+
match
1373
+
Eio.Flow.read_exact ctx.stdin buf;
1374
+
Cstruct.to_string buf
1375
+
with
1376
+
| "\n" -> Some acc
1377
+
| c -> loop (acc ^ c)
1378
+
| exception End_of_file -> None
1379
+
in
1380
+
loop ""
1381
+
in
1382
+
let rec loop acc = function
1383
+
| v :: vars, Ast.{ txt; _ } :: fs -> loop ((v, txt) :: acc) (vars, fs)
1384
+
| _, [] -> List.rev acc
1385
+
| [], lines ->
1386
+
let last_var, last_line = List.hd acc in
1387
+
List.rev
1388
+
((last_var, last_line ^ Ast.Fragment.join_list ~sep:"" lines)
1389
+
:: acc)
1390
+
in
1391
+
let fields =
1392
+
Option.map (fun s -> field_splitting ctx [ Ast.Fragment.make s ]) line
1393
+
in
1394
+
match fields with
1395
+
| None -> Exit.nonzero ctx 1
1396
+
| Some fs ->
1397
+
let vars = loop [] (vars, fs) in
1398
+
let state =
1399
+
List.fold_left
1400
+
(fun st (k, v) -> S.update st ~param:k v |> Result.get_ok)
1401
+
ctx.state vars
1402
+
in
1403
+
Exit.zero { ctx with state })
1368
1404
| Command _ ->
1369
1405
(* Handled separately *)
1370
1406
assert false
+35
test/built_ins.t
+35
test/built_ins.t
···
328
328
args: a b c d
329
329
args 2: c d
330
330
args 2: 2
331
+
332
+
15. Read
333
+
334
+
335
+
$ cat > test.sh << EOF
336
+
> echo "hello world" | read FOO BAR
337
+
> echo "FOO is \$FOO"
338
+
> echo "BAR is \$BAR"
339
+
> EOF
340
+
341
+
$ sh test.sh
342
+
FOO is
343
+
BAR is
344
+
$ msh test.sh
345
+
FOO is
346
+
BAR is
347
+
348
+
$ cat > test.sh << EOF
349
+
> echo hello > hello.txt
350
+
> echo world >> hello.txt
351
+
> echo finished >> hello.txt
352
+
>
353
+
> while read line; do
354
+
> echo "Got line: \$line"
355
+
> done < hello.txt
356
+
> EOF
357
+
358
+
$ sh test.sh
359
+
Got line: hello
360
+
Got line: world
361
+
Got line: finished
362
+
$ msh test.sh
363
+
Got line: hello
364
+
Got line: world
365
+
Got line: finished