open Types open Common open Printf open Config_file open Parser_helper open Tree type state = { per_files : (string, per_file) Hashtbl.t ; per_packages : (string, per_package) Hashtbl.t ; methods : (string, (pos * variable_used ref * prototype option) list) Hashtbl.t ; global_vars_used : ((context * string * string) * pos) list ref ; packages_being_classes : (string, unit) Hashtbl.t ; } type vars = { my_vars : ((context * string) * (pos * variable_used ref * prototype option)) list list ; our_vars : ((context * string) * (pos * variable_used ref * prototype option)) list list ; locally_imported : ((context * string) * (string * variable_used ref * prototype option)) list ; required_vars : (context * string * string) list ; current_package : per_package ; is_toplevel : bool ; write_only : bool ; state : state ; } let rec get_imported state current_package (package_name, (imports, pos)) = try let package_used = Hashtbl.find state.per_packages package_name in let exports = package_used.exports in let get_var_by_name var = let (b, prototype) = try sndter3 (Hashtbl.find package_used.vars_declared var) with Not_found -> try sndter3 (List.assoc var (get_imports state package_used)) with Not_found -> warn_with_pos [Warn_import_export] pos (sprintf "name %s is not defined in package %s" (variable2s var) package_name) ; ref Access_various, None in var, (package_name, b, prototype) in match imports with | None -> let re = match exports.special_export with | Some Re_export_all -> get_imports state package_used | Some Fake_export_all -> (* HACK: if package exporting-all is ignored, ignore package importing *) if List.mem package_name !ignored_packages then Tree.ignore_package current_package.package_name; Hashtbl.fold (fun var (_pos, b, proto) l -> (var, (package_name, b, proto)) :: l) package_used.vars_declared [] | _ -> [] in let l = List.map get_var_by_name exports.export_auto in re @ l | Some l -> let imports_vars = collect (function | I_raw, tag -> (try List.assoc tag exports.export_tags with Not_found -> warn_with_pos [Warn_import_export] pos (sprintf "package %s doesn't export tag %s" package_name tag) ; []) | variable -> if List.mem variable exports.export_ok || List.mem variable exports.export_auto then [ variable ] else (warn_with_pos [Warn_import_export] pos (sprintf "package %s doesn't export %s" package_name (variable2s variable)) ; []) ) l in List.map get_var_by_name imports_vars with Not_found -> [] and get_imports state package = match !(package.imported) with | Some l -> l | None -> let l = collect (get_imported state package) package.uses in package.imported := Some l ; l let do_para_comply_with_prototype para proto = match proto with | Some proto -> (match para with | [] as paras | [List [List paras]] | [List paras] -> if List.exists is_not_a_scalar paras then 0 else let len = List.length paras in if len < proto.proto_nb_min then -1 else (match proto.proto_nb_max with | Some max -> if len > max then 1 else 0 | None -> 0) | _ -> 0) | _ -> 0 let check_para_comply_with_prototype para proto = match para with | None -> () | Some(pos, para) -> match do_para_comply_with_prototype para proto with | -1 -> warn_with_pos [Warn_prototypes] pos "not enough parameters" | 1 -> warn_with_pos [Warn_prototypes] pos "too many parameters" | _ -> () let is_anonymous_variable_name s = String.length s > 1 && s.[0] = '_' let variable_used write_only used = if !used != Access_various then used := if write_only then Access_write_only else Access_various let is_my_declared vars t = List.exists (fun l -> List.mem_assoc t l && (variable_used vars.write_only (snd3 (List.assoc t l)) ; true) ) vars.my_vars let is_our_declared vars t = List.exists (fun l -> List.mem_assoc t l && (variable_used vars.write_only (snd3 (List.assoc t l)) ; true) ) vars.our_vars let is_var_declared_raw write_only state package var para = match try let _, used, proto = Hashtbl.find package.vars_declared var in Some(used, proto) with Not_found -> try let _, used, proto = List.assoc var (get_imports state package) in Some(used, proto) with Not_found -> None with | Some (used, proto) -> check_para_comply_with_prototype para proto ; variable_used write_only used ; true | None -> false let is_var_declared vars var para = List.mem_assoc var vars.locally_imported || is_var_declared_raw vars.write_only vars.state vars.current_package var para let is_global_var_declared vars (context, fq, name) para = try let package = Hashtbl.find vars.state.per_packages fq in is_var_declared_raw vars.write_only vars.state package (context, name) para with Not_found -> false let is_global_var context ident = match context with | I_scalar -> (match ident with | "@" | "!" | ">" | "\\" | "$" | "^A" | "'" | "/" | "?" | "<" | "^W" | "|" | "^I" | "&" | "." | "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" -> true | _ -> false) | I_array -> (match ident with | "ARGV" | "INC" -> true | _ -> false) | I_hash -> (match ident with | "ENV" | "SIG" -> true | _ -> false) | I_star -> (match ident with | "STDIN" | "STDOUT" | "STDERR" | "DATA" | "__FILE__" | "__LINE__" | "undef" -> true | _ -> false) | I_func -> (match ident with | "-b" | "-c" | "-d" | "-e" | "-f" | "-l" | "-r" | "-s" | "-w" | "-x" | "abs" | "alarm" | "atan2" | "bless" | "caller" | "chdir" | "chmod" | "chomp" | "chop" | "chown" | "chr" | "chroot" | "close" | "closedir" | "cos" | "crypt" | "defined" | "delete" | "die" | "each" | "endpwent" | "eof" | "eval" | "exec" | "exists" | "exit" | "fcntl" | "fileno" | "flock" | "formline" | "fork" | "gethostbyaddr" | "gethostbyname" | "getgrent" | "getgrnam" | "getgrgid" | "getppid" | "getpwent" | "getpwnam" | "getpwuid" | "getservbyname" | "glob" | "gmtime" | "goto" | "grep" | "hex" | "index" | "int" | "ioctl" | "join" | "keys" | "kill" | "last" | "lc" | "lcfirst" | "length" | "link" | "localtime" | "log" | "lstat" | "map" | "mkdir" | "next" | "no" | "oct" | "open" | "opendir" | "ord" | "pack" | "pipe" | "pop" | "print" | "printf" | "push" | "quotemeta" | "rand" | "read" | "readdir" | "readlink" | "redo" | "ref" | "rename" | "require" | "return" | "reverse" | "rindex" | "rmdir" | "scalar" | "seek" | "select" | "setpwent" | "shift" | "sin" | "sleep" | "sort" | "splice" | "split" | "sprintf" | "sqrt" | "stat" | "substr" | "symlink" | "syscall" | "sysopen" | "sysread" | "sysseek" | "system" | "syswrite" | "tie" | "time" | "uc" | "ucfirst" | "umask" | "undef" | "unlink" | "unpack" | "unshift" | "utime" | "values" | "vec" | "wait" | "waitpid" | "wantarray" | "warn" | "write" -> true | _ -> false) | _ -> false let check_variable (context, var) vars para = match var with | Ident(_, s, pos) when context <> I_func && is_anonymous_variable_name s && s <> "__FILE__" && s <> "__LINE__" -> warn_with_pos [Warn_normalized_expressions] pos (sprintf "variable %s must not be used\n (variable with name _XXX are reserved for unused variables)" (variable2s(context, string_of_fromparser var))) | Ident(Some pkg, _, _) when uses_external_package pkg || List.mem pkg !ignored_packages -> () | Ident(None, ident, pos) -> if is_my_declared vars (context, ident) || is_our_declared vars (context, ident) || is_var_declared vars (context, ident) para || is_global_var context ident then () else warn_with_pos [Warn_names] pos (if context = I_func then "unknown function " ^ ident else "undeclared variable " ^ variable2s(context, ident)) | Ident(Some fq, name, pos) -> if (fq = "CORE") && is_global_var context name || is_global_var_declared vars (context, fq, name) para then () else if context = I_func then warn_with_pos [Warn_names] pos ("unknown function " ^ string_of_fromparser var) else lpush vars.state.global_vars_used ((context, fq, name), pos) | _ -> () let declare_My vars (mys, pos) = let l_new = List.filter (fun (context, ident) -> if context = I_raw then if ident = "undef" then false else die_with_pos pos (sprintf "bad ident %s in my" ident) else true ) mys in let l_pre = List.hd vars.my_vars in List.iter (fun v -> if List.mem_assoc v l_pre then warn_with_pos [Warn_names] pos (sprintf "redeclared variable %s" (variable2s v)) ) l_new ; { vars with my_vars = (List.map (fun v -> v, (pos, ref Access_none, None)) l_new @ l_pre) :: List.tl vars.my_vars } let declare_Our vars (ours, pos) = match vars.our_vars with | [] -> vars (* we're at the toplevel, already declared in vars_declared *) | l_pre :: other -> List.iter (fun v -> if List.mem_assoc v l_pre && v <> (I_scalar, "_") then warn_with_pos [Warn_names] pos (sprintf "redeclared variable %s" (variable2s v)) ) ours ; { vars with our_vars = (List.map (fun v -> v, (pos, ref Access_none, None)) ours @ l_pre) :: other } let declare_My_our vars (my_or_our, l, pos) = match my_or_our with | "my" -> declare_My vars (l, pos) | "local" | "our" -> declare_Our vars (l, pos) | _ -> internal_error "declare_My_our" let un_parenthesize_one_elt_List = function | [List l] -> l | l -> l let check_unused_local_variables vars = List.iter (fun ((context, s as v), (pos, used, _proto)) -> if !used != Access_various then match s with | "BEGIN" | "END" | "DESTROY" -> () | "_" when context = I_array -> warn_with_pos [Warn_normalized_expressions] pos "if the function doesn't take any parameters, please use the empty prototype.\nexample \"sub foo() { ... }\"" | _ -> if s.[0] != '_' || s = "_" then let msg = if !used = Access_write_only then sprintf "variable %s assigned, but not read" else sprintf "unused variable %s" in warn_with_pos [Warn_names] pos (msg (variable2s v)) ) (List.hd vars.my_vars) let check_variables vars t = let rec check_variables_ vars t = fold_tree check vars t and check vars = function | Block l -> let vars' = { vars with my_vars = [] :: vars.my_vars ; our_vars = [] :: vars.our_vars } in let vars' = List.fold_left check_variables_ vars' l in check_unused_local_variables vars' ; Some vars | Call(Deref(I_func, Ident(None, "sort", _)), (Anonymous_sub(_, Block f, pos) :: l)) -> let vars = List.fold_left check_variables_ vars l in let vars' = { vars with my_vars = [ (I_scalar, "a"), (pos, ref Access_various, None) ; (I_scalar, "b"), (pos, ref Access_various, None) ] :: vars.my_vars ; our_vars = [] :: vars.our_vars } in let vars' = List.fold_left check_variables_ vars' f in check_unused_local_variables vars' ; Some vars | Call(Deref(I_func, Ident(None, func, func_pos)), Anonymous_sub(_, Block f, pos) :: l) when List.mem func [ "grep" ; "map" ; "substInFile" ; "map_index" ; "each_index" ; "partition" ; "find_index" ; "grep_index" ; "find" ; "any" ; "every" ; "uniq_" ] -> let vars = List.fold_left check_variables_ vars l in let vars' = { vars with my_vars = [] :: vars.my_vars ; our_vars = [(I_scalar, "_"), (pos, ref Access_various, None)] :: vars.our_vars } in let vars' = List.fold_left check_variables_ vars' f in check_unused_local_variables vars' ; check_variable (I_func, Ident(None, func, func_pos)) vars None ; Some vars | Call(Deref(I_func, (Ident _ as ident)), [ Deref(I_star, (Ident(None, "_", _))) ]) -> (* the &f case: allow access to @_ *) check_variable (I_func, ident) vars None ; let _ = is_my_declared vars (I_array, "_") in Some vars | Call(Deref(I_func, (Ident _ as ident)), [ List [ Deref(I_array, (Ident(None, "_", pos))) ] ]) -> (* special warning if @_ is unbound *) check_variable (I_func, ident) vars None ; if not (is_my_declared vars (I_array, "_")) then warn_with_pos [Warn_suggest_simpler] pos (sprintf "replace %s(@_) with &%s" (string_of_fromparser ident) (string_of_fromparser ident)) ; Some vars | Call(Deref(I_func, Ident(None, "require", _)), [Ident _]) -> Some vars | Call(Deref(I_func, Ident(None, "shift", pos)) as var, []) | Call(Deref(I_func, Ident(None, "pop", pos)) as var, []) -> check vars (Call(var, [ Deref(I_array, Ident(None, (if vars.is_toplevel then "ARGV" else "_"), pos)) ])) | Call(Deref(context, (Ident(_, _, pos) as var)), para) -> check_variable (context, var) vars (Some(pos, para)) ; let vars = List.fold_left check_variables_ vars para in Some vars (* | Call_op("=", -> List.fold_left (fold_tree f) env l*) | Call_op("while infix", [ expr ; (List [ Call_op("<>", _, _) ] as l) ], pos) | Call_op("for infix", [ expr ; l ], pos) -> let vars = check_variables_ vars l in let vars' = { vars with my_vars = [] :: vars.my_vars ; our_vars = [(I_scalar, "_"), (pos, ref Access_various, None)] :: vars.our_vars } in let vars' = check_variables_ vars' expr in if List.hd(vars'.my_vars) <> [] then warn_with_pos [Warn_traps] pos "you can't declare variables in foreach postfix"; Some vars | Call_op("foreach my", [my; expr; Block block], _) -> let vars = check_variables_ vars expr in let vars = check_variables_ vars (Block (my :: block)) in Some vars | Call_op(op, l, _) when op = "if" || op = "while" || op = "unless" || op = "until" -> let vars' = { vars with my_vars = [] :: vars.my_vars ; our_vars = [] :: vars.our_vars } in let vars' = List.fold_left check_variables_ vars' l in check_unused_local_variables vars' ; Some vars | Sub_declaration(Ident(fq, name, pos) as ident, perl_proto, Block body, kind) -> let vars = declare_Our vars ([ I_func, string_of_fromparser ident ], pos) in let my_vars, l = match has_proto perl_proto (Block body) with | Some(mys, mys_pos, body) -> [], My_our ("my", mys, mys_pos) :: body | _ -> let dont_check_use = kind = Glob_assign || fq = None && List.mem name ["DESTROY"] || Hashtbl.mem vars.state.packages_being_classes (some_or fq vars.current_package.package_name) in [(I_array, "_"), (pos, ref (if dont_check_use then Access_various else Access_none), None)], body in let local_vars = if fq = None && name = "AUTOLOAD" then [ (I_scalar, "AUTOLOAD"), (pos, ref Access_various, None) ] else [] in let vars' = { vars with my_vars = my_vars :: vars.my_vars ; our_vars = local_vars :: vars.our_vars ; is_toplevel = false } in let vars' = List.fold_left check_variables_ vars' l in check_unused_local_variables vars' ; Some vars | Anonymous_sub(_, Block l, pos) -> let vars' = { vars with my_vars = [(I_array, "_"), (pos, ref Access_various, None)] :: vars.my_vars ; is_toplevel = false } in let vars' = List.fold_left check_variables_ vars' l in check_unused_local_variables vars' ; Some vars | Call_op("foreach", [ expr ; Block l ], pos) -> let vars = check_variables_ vars expr in let vars' = { vars with my_vars = [] :: vars.my_vars ; our_vars = [(I_scalar, "_"), (pos, ref Access_various, None)] :: vars.our_vars } in let vars' = List.fold_left check_variables_ vars' l in check_unused_local_variables vars' ; Some vars | Anonymous_sub _ | Sub_declaration _ -> internal_error "check_variables" | Ident _ as var -> check_variable (I_star, var) vars None ; Some vars | My_our(my_or_our, mys, pos) -> Some(declare_My_our vars (my_or_our, mys, pos)) | Deref(context, (Ident _ as var)) -> check_variable (context, var) vars None ; Some vars | Deref_with(context, _, (Ident _ as var), para) -> let vars = check_variables_ vars para in check_variable (context, var) vars None ; Some vars | Call_op("=", [My_our(my_or_our, mys, pos); e], _) -> (* check e first *) let vars = check_variables_ vars e in List.iter (fun (context, var) -> if non_scalar_context context then warn_with_pos [Warn_prototypes] pos (sprintf "%s takes all the arguments, %s is undef in any case" (variable2s (context, var)) (variable2s (last mys))) ) (removelast mys) ; (* mys is never empty *) Some(declare_My_our vars (my_or_our, mys, pos)) | Call_op("if infix", [List [My_our _]; List [Num("0", _)]], _) -> None (* special allowed case *) | Call_op(op, List (My_our _ :: _) :: _, pos) | Call_op(op, My_our _ :: _, pos) | Call_op(op, Call_op("local", _, _) :: _, pos) -> if op <> "=" then warn_with_pos [Warn_traps] pos (sprintf "applying %s on a new initialized variable is wrong" op); None | Call_op("=", [ Deref(context, (Ident _ as var)) ; para], _) -> check_variable (context, var) { vars with write_only = true } None ; Some (check_variables_ vars para) | Call_op("=", [ List [ List l ] ; para], _) -> let vars = List.fold_left (fun vars -> function | Deref(context, (Ident _ as var)) -> check_variable (context, var) { vars with write_only = true } None ; vars | e -> check_variables_ vars e ) vars l in let vars = check_variables_ vars para in Some vars | Method_call(Raw_string(package_name, pos), Raw_string ("import", _), para) -> let args = match para with | [] -> None | [ List [v] ] -> Some(from_qw v) | _ -> die_with_pos pos "bad import statement" in let l = get_imported vars.state vars.current_package (package_name, (args, pos)) in let vars = if vars.is_toplevel then ( vars.current_package.imported := Some (get_imports vars.state vars.current_package @ l) ; vars ) else { vars with locally_imported = l @ vars.locally_imported } in Some vars | Method_call(Raw_string(pkg, _) as class_, Raw_string(method_, pos), para) -> let vars = List.fold_left check_variables_ vars para in let rec search pkg = if is_global_var_declared vars (I_func, pkg, method_) (Some(pos, [ List (class_ :: un_parenthesize_one_elt_List para) ])) then true else let package = Hashtbl.find vars.state.per_packages pkg in List.exists search (List.map fst (some_or package.isa [])) in (try if not (uses_external_package pkg || List.mem pkg !ignored_packages || search pkg || method_ = "bootstrap") then warn_with_pos [Warn_import_export] pos (sprintf "unknown method %s starting in package %s" method_ pkg); with Not_found -> warn_with_pos [Warn_import_export] pos (sprintf "unknown package %s" pkg)); Some vars | Method_call(o, Raw_string(method_, pos), para) -> let vars = check_variables_ vars o in let vars = List.fold_left check_variables_ vars para in (try let l = Hashtbl.find vars.state.methods method_ in let l_and = List.map (fun (_, used, proto) -> used, do_para_comply_with_prototype [ List (o :: un_parenthesize_one_elt_List para) ] proto) l in let l_and = match List.filter (fun (_, n) -> n = 0) l_and with | [] -> (match uniq (List.map snd l_and) with | [-1] -> warn_with_pos [Warn_prototypes] pos "not enough parameters" | [ 1] -> warn_with_pos [Warn_prototypes] pos "too many parameters" | _ -> warn_with_pos [Warn_prototypes] pos "not enough or too many parameters") ; l_and | l -> l in List.iter (fun (used, _) -> used := Access_various) l_and with Not_found -> if not (List.mem method_ [ "isa"; "can" ]) then warn_with_pos [Warn_names] pos ("unknown method " ^ method_)) ; Some vars | _ -> None in let vars = List.fold_left check_variables_ { vars with my_vars = [[]] } t in vars let check_tree state package = let vars = { my_vars = [[]]; our_vars = []; locally_imported = []; required_vars = []; current_package = package; state = state; is_toplevel = true; write_only = false } in if !Flags.verbose then print_endline_flush ("checking package " ^ package.package_name) ; let vars = check_variables vars package.body in check_unused_local_variables vars ; () let imported_add i1 i2 = if i1 = None && i2 = None then None else Some (some_or i1 [] @ some_or i2 []) let add_package_to_state state package = let package = try let existing_package = Hashtbl.find state.per_packages package.package_name in (*print_endline_flush (existing_package.file_name ^ " vs " ^ package.file_name); *) let vars_declared = existing_package.vars_declared in Hashtbl.iter (fun var pos -> Hashtbl.replace vars_declared var pos) package.vars_declared ; let p = { package_name = package.package_name ; has_package_name = package.has_package_name ; isa = if existing_package.isa = None then package.isa else existing_package.isa ; body = existing_package.body @ package.body ; uses = existing_package.uses @ package.uses ; required_packages = existing_package.required_packages @ package.required_packages ; vars_declared = vars_declared ; imported = ref (imported_add !(existing_package.imported) !(package.imported)) ; exports = { export_ok = existing_package.exports.export_ok @ package.exports.export_ok ; export_auto = existing_package.exports.export_auto @ package.exports.export_auto ; export_tags = existing_package.exports.export_tags @ package.exports.export_tags ; special_export = None } } in Hashtbl.replace state.per_packages package.package_name p ; p with Not_found -> package in Hashtbl.replace state.per_packages package.package_name package let add_file_to_files per_files file = Hashtbl.replace per_files file.file_name file let check_unused_vars package = Hashtbl.iter (fun (context, name) (pos, is_used, _proto) -> if not (!is_used != Access_various || List.mem name ["BEGIN"; "END"; "DESTROY"; "ISA"; "AUTOLOAD"; "EXPORT"; "EXPORT_OK"; "EXPORT_TAGS"]) then warn_with_pos [Warn_unused_global_vars] pos (sprintf "unused %s%s::%s" (if context = I_func then "function " else "variable " ^ context2s context) package.package_name name) ) package.vars_declared let arrange_global_vars_declared global_vars_declared state = Hashtbl.iter (fun (context, fq, name) (pos, proto) -> let package = try Hashtbl.find state.per_packages fq with Not_found -> (* creating a new shadow package *) let package = { package_name = fq; has_package_name = true ; exports = empty_exports ; imported = ref None ; vars_declared = Hashtbl.create 16 ; uses = [] ; required_packages = [] ; body = [] ; isa = None ; } in Hashtbl.add state.per_packages fq package ; package in if not (Hashtbl.mem package.vars_declared (context, name)) then Hashtbl.add package.vars_declared (context, name) (pos, ref Access_none, proto) (* otherwise dropping this second declaration *) ) global_vars_declared ; state let get_methods_available state = let classes = uniq ( hashtbl_collect (fun _ package -> match package.isa with | None -> if Hashtbl.mem package.vars_declared (I_func, "new") then [package] else [] | Some l -> package :: List.map (fun (pkg, pos) -> try Hashtbl.find state.per_packages pkg with Not_found -> die_with_pos pos ("bad package " ^ pkg) ) l ) state.per_packages ) in List.iter (fun pkg -> Hashtbl.replace state.packages_being_classes pkg.package_name () ; Hashtbl.iter (fun (context, v) (pos, is_used, proto) -> if context = I_func then let l = try Hashtbl.find state.methods v with Not_found -> [] in Hashtbl.replace state.methods v ((pos, is_used, proto) :: l) ) pkg.vars_declared ) classes ; state let default_per_files() = Hashtbl.create 16 let default_state per_files = { per_files = per_files; per_packages = Hashtbl.create 16; methods = Hashtbl.create 256 ; global_vars_used = ref []; packages_being_classes = Hashtbl.create 16 } let cache_cache = Hashtbl.create 16 let pkgs2s prefix l = let l = List.sort compare (List.map (fun pkg -> pkg.file_name) l) in String.concat "" (List.map (fun s -> prefix ^ s ^ "\n") l) let read_packages_from_cache per_files dir = if !Flags.no_cache || Hashtbl.mem cache_cache dir then () else try Hashtbl.add cache_cache dir (); let file = dir ^ "/.perl_checker.cache" in let fh = open_in file in let magic = input_line fh in if magic <> "perl_checker cache " ^ Build.date then () else let l = Marshal.from_channel fh in close_in fh ; let l = List.filter (fun file -> not (Hashtbl.mem per_files file.file_name) && (try file.build_time > mtime file.file_name with _ -> false) ) l in if !Flags.verbose then print_endline_flush (sprintf "using cached files\n%sfrom %s" (pkgs2s " " l) file) ; List.iter (fun file -> Info.add_a_file file.file_name file.lines_starts ; add_file_to_files per_files file ) l with Sys_error _ | End_of_file -> () let write_packages_cache per_files dir = try let l = List.filter (fun per_file -> per_file.require_name <> None) (hashtbl_values per_files) in let file = dir ^ "/.perl_checker.cache" in let fh = open_out file in output_string fh ("perl_checker cache " ^ Build.date ^ "\n") ; Marshal.to_channel fh l [] ; close_out fh ; if !Flags.verbose then print_endline_flush (sprintf "saving cached files\n%sin %s" (pkgs2s " " l) file) with Sys_error _ -> ()