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|
type options = {
positive: bool;
nonnegative: bool;
allow_float: bool;
ranges: string list;
relative: bool;
}
let default_opts = {
positive = false;
nonnegative = false;
allow_float = false;
ranges = [];
relative = false
}
let opts = ref default_opts
let number_arg = ref ""
let args = [
("--non-negative", Arg.Unit (fun () -> opts := {!opts with nonnegative=true}), "Check if the number is non-negative (>= 0)");
("--positive", Arg.Unit (fun () -> opts := {!opts with positive=true}), "Check if the number is positive (> 0)");
("--range", Arg.String (fun s -> let optsv = !opts in opts := {optsv with ranges=(s :: optsv.ranges)}), "Check if the number is within a range (inclusive)");
("--float", Arg.Unit (fun () -> opts := {!opts with allow_float=true}), "Allow floating-point numbers");
("--relative", Arg.Unit (fun () -> opts := {!opts with relative=true}), "Allow relative increment/decrement (+/-N)");
("--", Arg.Rest (fun s -> number_arg := s), "Interpret next item as an argument");
]
let usage = Printf.sprintf "Usage: %s [OPTIONS] <number>" Sys.argv.(0)
let () = if Array.length Sys.argv = 1 then (Arg.usage args usage; exit 1)
let () = Arg.parse args (fun s -> number_arg := s) usage
let check_nonnegative opts n =
if opts.nonnegative && (n < 0.0) then
failwith "Number should be non-negative."
let check_positive opts n =
if opts.positive && (n <= 0.0) then
failwith "Number should be positive"
let looks_like_number value =
try let _ = Pcre.exec ~pat:"^(\\-?)[0-9]+(\\.[0-9]+)?$" value in true
with Not_found -> false
let is_relative value =
try let _ = Pcre.exec ~pat:"^[+-][0-9]+$" value in true
with Not_found -> false
let number_string_from_relative value =
String.sub value 1 (String.length value - 1)
let get_relative opts s =
if opts.relative then
if not (is_relative s) then
failwith "Value is not a relative increment/decrement"
else number_string_from_relative s
else s
let number_of_string opts s =
if not (looks_like_number s) then Printf.ksprintf failwith "'%s' is not a valid number" s else
let n = float_of_string_opt s in
match n with
| Some n ->
(* If floats are explicitly allowed, just return the number. *)
if opts.allow_float then n
(* If floats are not explicitly allowed, check if the argument has a decimal separator in it.
If the argument string contains a dot but float_of_string didn't dislike it,
it's a valid number but not an integer.
*)
else if not (String.contains s '.') then n
(* If float_of_string returned None, the argument string is just garbage rather than a number. *)
else Printf.ksprintf failwith "'%s' is not a valid integer number" s
| None ->
Printf.ksprintf failwith "'%s' is not a valid number" s
let range_of_string opts s =
let rs = String.split_on_char '-' s |> List.map String.trim |> List.map (number_of_string opts) in
match rs with
| [l; r] -> (l, r)
| exception (Failure msg) ->
(* Some of the numbers in the range are bad. *)
Printf.ksprintf failwith "'%s' is not a valid number range: %s" s msg
| _ ->
(* The range itself if malformed, like 1-10-20. *)
Printf.ksprintf failwith "'%s' is not a valid number range" s
let check_ranges ranges n =
let in_range (l, r) n = (n >= l) && (n <= r) in
let res = List.fold_left (fun acc r -> acc || (in_range r n)) false ranges in
if not res then
Printf.ksprintf failwith "Number is not in any of allowed ranges"
let () = try
let opts = !opts in
let s = get_relative opts !number_arg in
let n = number_of_string opts s in
check_nonnegative opts n;
check_positive opts n;
if opts.ranges <> [] then
let ranges = List.map (range_of_string opts) opts.ranges in
check_ranges ranges n
with (Failure err) ->
print_endline err;
exit 1
|
